title: Error: The source control operation failed because the revisions
body: <p>I've installed Xcode 7, and now always get this message when I select "commit" from xcode menu.</p>
  
  <p>"The source control operation failed because the revisions... could not be found."</p>
  
  <p>Any idea?  :)</p>
  
  <p><a href="https://i.stack.imgur.com/yw2Ut.png" rel="noreferrer"><img src="https://i.stack.imgur.com/yw2Ut.png" alt="error message"></a></p>