title: Fatal error unpacking a tree object during a git svn fetch
body: <p>When running get svn fetch to pull the latest new branches from the upstream svn repository I got this error:</p>
  
  <pre><code>$ git svn fetch
  fatal: failed to unpack tree object 5ecb324e8b8fcb918acb253f33edc6ce49e49e0d
  read-tree 5ecb324e8b8fcb918acb253f33edc6ce49e49e0d: command returned error: 128
  </code></pre>
  
  <p>Now every attempt at git svn on that local repo results in the same error.  Originally I was running git version 1.5.6.4_0 and after the error I tried updating to 1.6.0.2_2 and the problem still persists.</p>
  
  <p>Is there any way to clean up this corruption?  A fresh git svn clone of the upstream repository is fine, but I'd like to preserve my existing setup.  I've looked through the docs and googled for the problem with no luck.</p>