title: PR and branches after change email
body: <p>I faced with strange bihavior.
  I have <a href="https://github.com/moteus/fusionpbx" rel="nofollow">fork</a> of <a href="https://github.com/fusionpbx/fusionpbx" rel="nofollow">FusionPBX</a> repo.
  I create new branch and make <a href="https://github.com/fusionpbx/fusionpbx/pull/1613" rel="nofollow">PR</a> and it was accepted.
  But github did not display it as merge branch but just like regular commit.
  Also it does not display it like merge in repo graph.
  When I try remove branch from local repo I get.</p>
  
  <pre><code>error: The branch 'escene_phonebook' is not fully merged.
  If you are sure you want to delete it, run 'git branch -D escene_phonebook'.
  </code></pre>
  
  <p>On local repo I make</p>
  
  <pre><code>git fetch upstream
  git checkout master
  git merge upstream/master
  </code></pre>
  
  <p>This bihavior starts after I change my email on github and on local git config. I add new email to github account and set it as primary. Also I set this email in global settings on my machine. <code>git config user.email</code> display correct new address.</p>