Fix fatal in commit message parser
Summary:
See D1195, which fataled this daemon.
https://secure.phabricator.com/daemon/log/2966/
Test Plan: Applied this patch to secure.phabricator.com, restarted daemon, it
picked up D1203.
Reviewers: btrahan, jungejason, mareksapota
Reviewed By: btrahan
CC: aran, btrahan, mareksapota
Differential Revision: 1204