Automatically correct release status

Summary: This automatically moves a release into "ready for deploy" status if both the prepare build and the approval build have passed, but the build is at some point prior.

Test Plan: Tested locally by setting the status manually while prepare and approval builds were passed.

Reviewers: waynea, #koi, lucasr

Reviewed By: #koi, lucasr

Differential Revision: https://code.pageuppeople.com/D3368

Risk Rating: 1