title: Cannot remove entries from nonexistent easy-install.pth file
body: <p>When using python/pip to install a module, it is possible to receive the error <code>Cannot remove entries from nonexistent file &lt;some path&gt;/easy-install.pth</code></p>
  
  <p>There are a couple of Q/A's here on Stack Overflow about very specific cases of this (e.g. Anaconda and Tensorflow).  I'm more curious about the general case.  What exactly does this error mean, and what causes it?  </p>
  
  <p>(For my specific case, I am trying to install the docker3.4.0 module with python2.7/pip10.0.1, and adding <code>--ignore-installed</code> to the pip arguments does not remove the error.  I was able to work around this issue by creating an empty <code>easy-install.pth</code> at the specified location, but  that seems like an unhealthy fix.)</p>
  
  <p>Why would an <code>easy-install.pth</code> file go missing, and what are the possible repercussions of a missing <code>easy-install.pth</code>?</p>