title: git filter-branch --tree-filter with --since returns "Found nothing to rewrite"
body: <p>I'm trying to perform a command on all commits since a certain date:</p>
  
  <p><code>
  git filter-branch -f --tree-filter &lt;command&gt; HEAD -- --since="2014-06-01 13:37" &lt;name-of-branch&gt;
  </code></p>
  
  <p>Unfortunately it always outputs <code>Found nothing to rewrite</code> and stops. Everything after <code>--</code> should be treated as an option for <code>rev-list</code> so if I try:</p>
  
  <p><code>
  git rev-list --since="2014-06-01 13:37" &lt;name-of-branch&gt;
  </code></p>
  
  <p>I'll get the correct set of all revisions since 2014-06-01.</p>
  
  <p>What am I doing wrong?</p>