title: git branch -d <BRANCH>: Fatal - Couldn't look up commit object for HEAD
body: <p>Say I am in a bare repository (a remote), if I try to delete a branch with <code>git branch -d &lt;branch_name&gt;</code> I get the following error:</p>
  
  <pre><code>fatal: Couldn't look up commit object for HEAD
  </code></pre>
  
  <p>Why? Is there a reason why I should be unable to delete branches from a  bare repository?</p>