title: gerrit/git setup messed up when network disconnected in the middle. How to abandon the partial commits?
body: <p>I was pushing my changes from local git repo to Gerrit using "git push origin HEAD:refs/for/master" when my network disconnected.</p>
  
  <p>Now when I try to rerun it, I get:</p>
  
  <p>Counting objects: 40, done.
  Delta compression using up to 8 threads.
  Compressing objects: 100% (28/28), done.
  Writing objects: 100% (36/36), 2.23 MiB, done.
  Total 36 (delta 4), reused 5 (delta 0)
  remote: Resolving deltas: 100% (4/4)
  remote: Processing changes: refs: 1, done<br>
  To ssh://@:29418/scaligent.git
   ! [remote rejected] HEAD -> refs/for/master (change 57 closed)
  error: failed to push some refs to 'ssh://@:29418/scaligent.git'</p>
  
  <p>How do I clean up the state?</p>