title: Revert the use of filter-branch in Git
body: <p>I used git filter-branch and screwed something up and accidentally rewrote sections of the history I didn't want to. I was trying to change one name and accidentally changed every single commit (instead of only ones with a specific name).</p>
  
  <p>I know that 'git filter-branch' keeps a backup at refs/original, but I don't know how to revert the master branch to this old version. What's the git command to do this?</p>