title: Pip broken on Ubuntu 14.4 after package upgrade
body: <p>I was trying to upgrade the python requests package on an EC2 ubuntu 14.4 instance. after doing this, which did not throw an error I ran </p>
  
  <pre><code>pip freeze
  </code></pre>
  
  <p>and got:</p>
  
  <pre><code>ubuntu@ip-172-31-28-196:~$ pip freeze
  Traceback (most recent call last):
    File "/usr/bin/pip", line 9, in &lt;module&gt;
      load_entry_point('pip==1.5.4', 'console_scripts', 'pip')()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 351, in load_entry_point
      return get_distribution(dist).load_entry_point(group, name)
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2363, in load_entry_poin
      return ep.load()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2088, in load
      entry = __import__(self.module_name, globals(),globals(), ['__name__'])
    File "/usr/lib/python2.7/dist-packages/pip/__init__.py", line 11, in &lt;module&gt;
      from pip.vcs import git, mercurial, subversion, bazaar  # noqa
    File "/usr/lib/python2.7/dist-packages/pip/vcs/mercurial.py", line 9, in &lt;module&gt;
      from pip.download import path_to_url
    File "/usr/lib/python2.7/dist-packages/pip/download.py", line 25, in &lt;module&gt;
      from requests.compat import IncompleteRead
  ImportError: cannot import name IncompleteRead
  ubuntu@ip-172-31-28-196:~$ sudo apt-get remove python-pip
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  The following packages were automatically installed and are no longer required:
    python-colorama python-distlib python-html5lib
  Use 'apt-get autoremove' to remove them.
  The following packages will be REMOVED:
    python-pip
  0 upgraded, 0 newly installed, 1 to remove and 64 not upgraded.
  After this operation, 479 kB disk space will be freed.
  Do you want to continue? [Y/n] Y
  (Reading database ... 58701 files and directories currently installed.)
  Removing python-pip (1.5.4-1) ...
  Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
  ubuntu@ip-172-31-28-196:~$ sudo apt-get install python-pip
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  Recommended packages:
    python-dev-all
  The following NEW packages will be installed:
    python-pip
  0 upgraded, 1 newly installed, 0 to remove and 64 not upgraded.
  Need to get 0 B/97.7 kB of archives.
  After this operation, 479 kB of additional disk space will be used.
  Selecting previously unselected package python-pip.
  (Reading database ... 58626 files and directories currently installed.)
  Preparing to unpack .../python-pip_1.5.4-1_all.deb ...
  Unpacking python-pip (1.5.4-1) ...
  Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
  Setting up python-pip (1.5.4-1) ...
  ubuntu@ip-172-31-28-196:~$ pip freeze
  Traceback (most recent call last):
    File "/usr/bin/pip", line 9, in &lt;module&gt;
      load_entry_point('pip==1.5.4', 'console_scripts', 'pip')()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 351, in load_entry_point
      return get_distribution(dist).load_entry_point(group, name)
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2363, in load_entry_poin
      return ep.load()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2088, in load
      entry = __import__(self.module_name, globals(),globals(), ['__name__'])
    File "/usr/lib/python2.7/dist-packages/pip/__init__.py", line 11, in &lt;module&gt;
      from pip.vcs import git, mercurial, subversion, bazaar  # noqa
    File "/usr/lib/python2.7/dist-packages/pip/vcs/mercurial.py", line 9, in &lt;module&gt;
      from pip.download import path_to_url
    File "/usr/lib/python2.7/dist-packages/pip/download.py", line 25, in &lt;module&gt;
      from requests.compat import IncompleteRead
  ImportError: cannot import name IncompleteRead
  ubuntu@ip-172-31-28-196:~$ sudo apt-get --purge remove python-pip
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  The following packages were automatically installed and are no longer required:
    python-colorama python-distlib python-html5lib
  Use 'apt-get autoremove' to remove them.
  The following packages will be REMOVED:
    python-pip*
  0 upgraded, 0 newly installed, 1 to remove and 64 not upgraded.
  After this operation, 479 kB disk space will be freed.
  Do you want to continue? [Y/n] Y
  (Reading database ... 58701 files and directories currently installed.)
  Removing python-pip (1.5.4-1) ...
  Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
  ubuntu@ip-172-31-28-196:~$ sudo apt-get install python-pip
  Reading package lists... Done
  Building dependency tree
  Reading state information... Done
  Recommended packages:
    python-dev-all
  The following NEW packages will be installed:
    python-pip
  0 upgraded, 1 newly installed, 0 to remove and 64 not upgraded.
  Need to get 0 B/97.7 kB of archives.
  After this operation, 479 kB of additional disk space will be used.
  Selecting previously unselected package python-pip.
  (Reading database ... 58626 files and directories currently installed.)
  Preparing to unpack .../python-pip_1.5.4-1_all.deb ...
  Unpacking python-pip (1.5.4-1) ...
  Processing triggers for man-db (2.6.7.1-1ubuntu1) ...
  Setting up python-pip (1.5.4-1) ...
  ubuntu@ip-172-31-28-196:~$ pip freeze
  Traceback (most recent call last):
    File "/usr/bin/pip", line 9, in &lt;module&gt;
      load_entry_point('pip==1.5.4', 'console_scripts', 'pip')()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 351, in load_entry_point
      return get_distribution(dist).load_entry_point(group, name)
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2363, in load_entry_poin
      return ep.load()
    File "/usr/lib/python2.7/dist-packages/pkg_resources.py", line 2088, in load
      entry = __import__(self.module_name, globals(),globals(), ['__name__'])
    File "/usr/lib/python2.7/dist-packages/pip/__init__.py", line 11, in &lt;module&gt;
      from pip.vcs import git, mercurial, subversion, bazaar  # noqa
    File "/usr/lib/python2.7/dist-packages/pip/vcs/mercurial.py", line 9, in &lt;module&gt;
      from pip.download import path_to_url
    File "/usr/lib/python2.7/dist-packages/pip/download.py", line 25, in &lt;module&gt;
      from requests.compat import IncompleteRead
  ImportError: cannot import name IncompleteRead
  ubuntu@ip-172-31-28-196:~$
  </code></pre>
  
  <p>As you can see I've tried to uninstall and reinstall pip in various ways to no avail. How can I get it working again?</p>
  
  <p>edit:</p>
  
  <pre><code> ubuntu@ip-172-31-28-196:~$ sudo python get-pip.py
   The directory '/home/ubuntu/.cache/pip/log' or its parent directory is not owned by the current user
    and the debug log has been disabled. Please check the permissions and owner of that directory. If e
   xecuting pip with sudo, you may want the -H flag.
   The directory '/home/ubuntu/.cache/pip/http' or its parent directory is not owned by the current use
   r and the cache has been disabled. Please check the permissions and owner of that directory. If exec
   uting pip with sudo, you may want the -H flag.
   The directory '/home/ubuntu/.cache/pip/http' or its parent directory is not owned by the current use
   r and the cache has been disabled. Please check the permissions and owner of that directory. If exec
   uting pip with sudo, you may want the -H flag.
   Collecting pip
     Downloading pip-6.0.8-py2.py3-none-any.whl (1.3MB)
       100% |################################| 1.3MB 370kB/s
   Installing collected packages: pip     
  
   Successfully installed pip-6.0.8
   ubuntu@ip-172-31-28-196:~$ pip freeze
   -bash: /usr/bin/pip: No such file or directory
   ubuntu@ip-172-31-28-196:~$ sudo -H python get-pip.py
   Requirement already up-to-date: pip in /usr/local/lib/python2.7/dist-packages
   ubuntu@ip-172-31-28-196:~$ sudo apt-get --purge remove python-pip
   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   Package 'python-pip' is not installed, so not removed
   The following packages were automatically installed and are no longer required:
     python-colorama python-distlib python-html5lib
   Use 'apt-get autoremove' to remove them.
   0 upgraded, 0 newly installed, 0 to remove and 64 not upgraded.
   ubuntu@ip-172-31-28-196:~$ sudo -H python get-pip.py
   Requirement already up-to-date: pip in /usr/local/lib/python2.7/dist-packages
   ubuntu@ip-172-31-28-196:~$ pip freeze
   -bash: /usr/bin/pip: No such file or directory
  </code></pre>