title: fatal: A branch named 'gh-pages' already exists
body: <p>I made a template sale website (gatsby / react).  I cloned my template GitHub repo and changed the remote origin to a new private repo, pushing to which works fine.</p>
  <p>I deploy to gh-pages with npm srcipt <code>&quot;deploy&quot;: &quot;gatsby build --prefix-paths &amp;&amp; gh-pages -d public&quot;</code>
  The first time I ran this command it seemed to stall so I <code>control c</code>'d out of it. Now, when I try to deploy I get the error &quot;fatal: A branch named 'gh-pages' already exists.&quot;</p>
  <p><code>git branch -a</code> shows:
  <code>remotes/origin/HEAD -&gt; origin/master</code>
  <code>remotes/origin/gh-pages</code>
  <code>remotes/origin/master </code></p>
  <p>But there is not a gh-pages branch on gitHub.</p>
  <p>I tried <code>rm -rf node_modules/gh-pages/.cache</code> didn't work.
  Also, <code>git push origin --delete gh-pages</code> which gave
  &quot;error: unable to delete 'gh-pages': remote ref does not exist&quot;.</p>
  <p>I uninstalled and reinstalled gh-pages.</p>