title: When running repo sync error: Exited sync due to fetch errors
body: <p>I'm trying to sync my jb repository but I receive this odd error.
  funny thing is that it does not always crash at the same point (though it might be just a synchronization issue since I add -j10).</p>
  
  <p>command:
  <code>$ repo sync -j10</code></p>
  
  <p>error:
  <code>error: Exited sync due to fetch errors</code></p>
  
  <p>I'm aware of the possibility of starting fresh but this is somewhat annoying and I get this issue often enough.</p>
  
  <p>Can anyone suggest a faster solution? </p>