title: ImportError: module 'setuptools.dist' has no 'check_specifier' attribute
body: <p>Ceph teuthology installation fails with following error on Ubuntu 14.04, kernel 4.4.0-51-generic:</p>
  
  <blockquote>
  <pre><code>ImportError: &lt;module 'setuptools.dist' from '/usr/lib/python2.7/dist-packages/setuptools/dist.pyc'&gt; has no 'check_specifier' attribute
  </code></pre>
  </blockquote>