title: Cannot change username on Gerrit, after changing github username
body: <p>I had github username &quot;Old_UserName&quot; and it worked well with gerrit, as in, I was able to commit and get a review.</p>
  <p>On the gerrit website (review.openswitch.net) the username &quot;Old_UserName&quot; was automatically setup using github's credentials.</p>
  <p>Everything worked fine, until I changed my username on github to &quot;New_UserName&quot;. But on gerrit website (review.openswitch.net), I still see &quot;Old_UserName&quot;.<br />
  Help appreciated.</p>
  <p>I want to get things working, change of username is NOT that important, so I can even revert back to my old username if that's the only solution.</p>
  <p>Here is the konsole output of the git review:</p>
  <pre><code>git review
  remote: Resolving deltas: 100% (5/5)
  remote: Processing changes: refs: 1, done
  remote:
  remote: ERROR:  In commit 00blah000blah000blah000id000
  remote: ERROR:  committer email address correct.email.address@domain.com
  remote: ERROR:  does not match your user account.
  remote: ERROR:
  remote: ERROR:  You have not registered any email addresses.
  remote: ERROR:
  remote: ERROR:  To register an email address, please visit:
  remote: ERROR:  https://review.openswitch.net/#/settings/contact
  remote:
  remote:
  To ssh://Old_UserName@review.openswitch.net:9XXX1/openswitch/ops-build
   ! [remote rejected] HEAD -&gt; refs/publish/master (invalid committer)
  error: failed to push some refs to 'ssh://Old_UserName@review.openswitch.net:9XXX1/openswitch/ops-build'
  </code></pre>
  <p>I have tried to register the same email address again.<br />
  This email address was linked with it earlier too.<br />
  I get a verification email form gerrit. But, when I click on the verification link, it gives an &quot;invalid token&quot; error.</p>
  <h3>Constraints:</h3>
  <p>I cannot change my email id (since it's an organization email) or create a new git hub account for the same.</p>