Summary: When updating the status of a task via commit, transaction should show responsible commit and status update if it was changed.
Test Plan: Push a commit "Fixes Txx", transaction should include status update and commit number.
Reviewers: #blessed_reviewers, epriestley
Reviewed By: #blessed_reviewers, epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T6637
Differential Revision: https://secure.phabricator.com/D11230