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
Btw, @jrbl I'm not sure @dcadams's usage counts as the "Oxford comma", since even though it was before an "and" it wasn't used in a list. (But that's neither here nor there of course.)