title: git fetch origin --prune doesn't delete local branches?
body: <p>At one point I thought that <code>git fetch origin --prune</code> deleted local branches that were no longer present on the server. Somehow this is not my experience at the moment.</p>
  
  <p>I ran this command, and the local branch was not deleted. It is <em>not</em> currently checked out. I ran <code>git branch -vv</code> to check this info, and I see</p>
  
  <pre><code>feature/MyGreatFeature           f30efc7 [origin/feature/MyGreatFeature: gone]
  </code></pre>
  
  <p>So it seems to know that it is gone. Why would it not delete my local branch?</p>
  
  <p>Running <code>git version 2.7.4 (Apple Git-66)</code></p>