title: Error in upgrading pip on Linux
body: <p>I am running the command on linux system as :</p>
  
  <pre><code>sudo pip install --upgrade pip
  </code></pre>
  
  <p>But I am getting the error message as :</p>
  
  <pre><code>pkg_resources.DistributionNotFound: The 'pip==6.1.1' distribution was not found and is required by the application
  </code></pre>
  
  <p>Where as, if I go and check the <code>pip --version</code>, I get the response as :</p>
  
  <pre><code>pip 9.0.1 from /usr/local/lib/python2.7/site-packages (python 2.7)
  </code></pre>
  
  <p>Why do I need <code>'pip==6.1.1' distribution</code> and how do i get it ?</p>