title: How can I display vcs revision of Python package installed with pip from vcs?
body: <p>After installing some package with pip from vcs like this<br>
  <code>pip install git+https://github.com/kennethreitz/requests.git@355b97165c#requests</code><br>
  how can I display the vcs revision/commit/branch/tag (355b97165c in this example) used to install it?</p>