When remote builds fail, demote revisions to "Changes Planned + But, Still A Draft"

Summary:
Depends on D19286. Ref T13110. After builds fail remote builds, put revisions back in the author's queue.

This doesn't actually notify the author quite yet.

Test Plan: Made a failing build plan run on revisions, created a revision, saw it demote after builds failed.

Maniphest Tasks: T13110

Differential Revision: https://secure.phabricator.com/D19287