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
No it doesn't. PeerworkflowItem.scored is used in the context that only those with scored = 1 are evaluated for the score.