Fix up the ora2 scores affected by the track changes bug.

  For affected assessments:
    - Sets PeerWorkflowItem.scored = 0 if currently = 1
    - Recalculates the score for the submission
    - If new score > old score, update the Score.points_earned with the new score
tut tut, not a track changes bug. Track changes made it possible for us to detect a scoring bug.

Perhaps just refer to the bug, or to its fix, by commit or PR number? That gives people all the context they could ever want.  Here's Steven's bugfix: https://github.com/edx/edx-ora2/pull/628