title: How to add gerrit change ID to an older commit?
body: <p>Few commits back, I made a commit that doesn't have change ID. This unfortunately happens whenever you merge branches in source-tree without unchecking "Commit merge immediately".</p>
  
  <p>I urgently need to push the code to Gerrit now, but I can't because one of the commits doesn't have change ID.</p>
  
  <p>How can I re-add change ID to an older commit?</p>