Allow release to be marked as broken at any time

Summary: This allows release to be marked as broken at any time (excluding when it's already marked as broken or in a status where it can be accepted / rejected).

Test Plan: Tested with other releases in other statuses.

Reviewers: waynea, #koi

Reviewed By: waynea, #koi

Differential Revision: https://code.pageuppeople.com/D3554

Risk Rating: 1