Summary:
Ref T4245. Two effects:
- First, let hooks work for future repositories without callsigns.
- Second, provide a better error when users push directly to hosted repositories.
Test Plan: Ran `bin/commit-hook PHID-REPO-xxx`.
Reviewers: chad, avivey
Reviewed By: avivey
Maniphest Tasks: T4245
Differential Revision: https://secure.phabricator.com/D15293
973b8ace86