title: error: cannot lock ref.. 'refs/tags' exists; cannot create 'refs/tags/
body: <p>I'm getting a strange "cannot lock ref" error when trying to pull changes from github.  I've tried git gc, and looked around for similar errors but can't find a solution.</p>
  
  <pre><code>&gt; git pull
  error: cannot lock ref 'refs/tags/v2.8': 'refs/tags' exists; cannot create 'refs/tags/v2.8'
  From github.com:k3it/qsorder
   ! [new tag]         v2.8       -&gt; v2.8  (unable to update local ref)
  error: cannot lock ref 'refs/tags/v2.9': 'refs/tags' exists; cannot create 'refs/tags/v2.9'
   ! [new tag]         v2.9       -&gt; v2.9  (unable to update local ref)
  </code></pre>