title: Git rebase failing
body: <p>I'm trying to rebase the work of a colleague.</p>
  
  <p>First, I get a ton of conflicts where &lt;&lt;&lt;&lt;&lt; head seams to contain the new code. </p>
  
  <p>Then after a while I get the following error:</p>
  
  <pre><code>fatal: update_ref failed for ref 'refs/heads/dev_504': 
  cannot lock ref     'refs/heads/dev_504': ref refs/heads/dev_504 is at
   XXXXXXX 
   but expected     XXXXXXXX
  Could not move back to refs/heads/dev_504
  </code></pre>
  
  <p>Then if I try to continue anyway I get the following error:</p>
  
  <pre><code>fatal: cannot resume: .git/rebase-apply/final-commit does not exist.
  </code></pre>
  
  <p>How can I fix this so the rebase won't give an error?</p>