title: gerrit Unable to create changes: LOCK_FAILURE when pushing for review
body: <p>I've been handed numerous git repos which I have created mirrors of. I'm getting following error when trying to push to gerrit for review</p>
  
  <pre><code>blake-macbook:repo blake$ git push ssh://gerrit-new/repo HEAD:refs/for/master
  Counting objects: 3, done.
  Delta compression using up to 4 threads.
  Compressing objects: 100% (3/3), done.
  Writing objects: 100% (3/3), 359 bytes | 0 bytes/s, done.
  Total 3 (delta 2), reused 0 (delta 0)
  remote: Resolving deltas: 100% (2/2)
  remote: Processing changes: refs: 2, done    
  To ssh://gerrit-new/repo
  ! [remote rejected] HEAD -&gt; refs/for/master (Unable to create changes:LOCK_FAILURE)
  error: failed to push some refs to 'ssh://gerrit-new/repo'
  </code></pre>
  
  <p>Gerrit is running as its own user. I've checked the filesystem permissions and have refreshed them just in case</p>
  
  <pre><code>chown -R gerrit.gerrit /home/gerrit/review-site
  </code></pre>
  
  <p>Logs are showing nothing useful</p>
  
  <pre><code>[2016-09-08 00:07:45,071] [ReceiveCommits-1] ERROR com.google.gerrit.server.git.ReceiveCommits : Command CREATE on repo:refs/changes/54/54/1 not completed: LOCK_FAILURE
  [2016-09-08 00:07:45,072] [ReceiveCommits-1] ERROR com.google.gerrit.server.git.ReceiveCommits : Only 0 of 1 new change refs created in repo; aborting
  </code></pre>
  
  <p>I've created a group call "Project Leads", granted pretty pretty much every permission in the default All-Projects access scheme, ensured that my project inherits from All-Projects.</p>
  
  <p>I've also added my test user to the Administrators group ... no dice. Same error.</p>
  
  <p>weird thing is that it was working fine 5 days ago. The only thing I have done is check out a new branch, try to commit to the new branch (got the error) and now the error is present for every commit (well, everything I've attempted)</p>
  
  <p>If I bypass review it pushes just fine (suboptimal workaround though)</p>
  
  <p>Any help appreciated</p>
  
  <p>EDIT: in case you are wondering about the ssh server/port i have it set up on ssh config file</p>
  
  <pre><code>Host gerrit-new
      HostName        &lt;server&gt;
      Port            29418
      User            &lt;user&gt;
      IdentityFile    ~/.ssh/&lt;priv_key.rsa&gt;
  </code></pre>
  
  <p>EDIT2: also tried restart, reindex, reboot, and manually deleting the write.lock files</p>