title: Git error: previous rebase directory .git/rebase-apply still exists but mbox given
body: <p>I'm trying to apply a patch, which I took from <a href="http://www.winehq.org/pipermail/wine-devel/2014-May/104356.html">http://www.winehq.org/pipermail/wine-devel/2014-May/104356.html</a>. I copied it into a text editor, and saved it as <code>my.patch</code> (I needed to fix the email, it had been obfuscated).</p>
  
  <p>I tried to apply it with Git, but I'm getting this error:</p>
  
  <pre><code>sashoalm@sashoalm-VirtualBox:~/Desktop/wine-git$ git am --signoff &lt;my.patch
  previous rebase directory /home/sashoalm/Desktop/wine-git/.git/rebase-apply still exists but mbox given.
  </code></pre>
  
  <p>This cryptic error message gives me no idea what's wrong or what I need to do to make it work. What does this error mean? And how do I fix it?</p>