title: 'pip==9.0.1' distribution was not found and is required by the application
body: <p>I think my pip is broken. I've tried everything from doing force reinstall to update everything but nothing seems to work.</p>
  
  <p>when I do <code>pip2 -v</code> then I get the following:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/usr/local/bin/pip2", line 6, in &lt;module&gt;
      from pkg_resources import load_entry_point
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3144, in &lt;module&gt;
      @_call_aside
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3128, in _call_aside
      f(*args, **kwargs)
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 3157, in _initialize_master_working_set
      working_set = WorkingSet._build_master()
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 666, in _build_master
      ws.require(__requires__)
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 984, in require
      needed = self.resolve(parse_requirements(requirements))
    File "/usr/local/lib/python2.7/site-packages/pkg_resources/__init__.py", line 870, in resolve
      raise DistributionNotFound(req, requirers)
  pkg_resources.DistributionNotFound: The 'pip==9.0.1' distribution was not found and is required by the application
  </code></pre>
  
  <p>when I do <code>pip -v</code> then I get the following:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/bin/pip", line 7, in &lt;module&gt;
      from pip._internal import main
  ImportError: No module named pip._internal
  </code></pre>
  
  <p>FYI: I'm on <code>Mac OSX</code> and am using <code>Python 2.7.14</code></p>
  
  <p>Please help!!</p>