title: unable to update python package psutil
body: <p>when i check the version of psutil in python it says i have version <code>0.5.0</code>:</p>
  
  <pre><code>$ uname -a
  Linux mypc 3.2.0-4-amd64 #1 SMP Debian 3.2.60-1+deb7u3 x86_64 GNU/Linux
  $ python
  Python 2.7.3 (default, Mar 13 2014, 11:03:55) 
  [GCC 4.7.2] on linux2
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import psutil
  &gt;&gt;&gt; psutil.__version__
  '0.5.0'
  &gt;&gt;&gt; psutil.virtual_memory()
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  AttributeError: 'module' object has no attribute 'virtual_memory'
  &gt;&gt;&gt; psutil.__file__
  '/usr/lib/pymodules/python2.7/psutil/__init__.pyc'
  </code></pre>
  
  <p>i want to upgrade to a newer version of psutil which has the <code>virtual_memory()</code> method:</p>
  
  <pre><code>$ sudo pip install 'psutil==2.2.1' --upgrade
  Requirement already up-to-date: psutil==2.2.1 in /usr/local/lib/python2.7/dist-packages
  Cleaning up...
  </code></pre>
  
  <p>the two different paths for the same package imply that <code>psutil</code> is installed twice:</p>
  
  <pre><code>/usr/local/lib/python2.7/dist-packages
  /usr/lib/pymodules/python2.7/psutil/__init__.pyc
  </code></pre>
  
  <p>i only want <code>psutil</code> version <code>2.2.1</code>. what is the best way to clean up the other unwanted <code>0.5.0</code> package and only keep this later one?</p>
  
  <hr>
  
  <p>as per the comments - checking if either of the above paths were installed through <code>dpkg</code>:</p>
  
  <pre><code>$ dpkg -S /usr/local/lib/python2.7/dist-packages
  dpkg-query: no path found matching pattern /usr/local/lib/python2.7/dist-packages
  $ dpkg -S /usr/lib/pymodules/python2.7/psutil/__init__.pyc
  dpkg-query: no path found matching pattern /usr/lib/pymodules/python2.7/psutil/__init__.pyc
  </code></pre>