R1:9da6ec208111

Make updates of rejected revisions behave correctly again

Summary:
Ref T2222. Ref T4481. Specifically:

- When a revision is updated, change all "Reject" reviewers to "Reject Prior".
- Change status to "Needs Review".
- Update the state logic to account for this properly.

Test Plan:
- Created a revision as user A, with B as a reviewer.
- Rejected as B.
- Updated the revision as A.
- Saw revision in "needs review" state, with B as a "Rejected Prior" reviewer.

Reviewers: btrahan

Reviewed By…