R1:25fade500890

Add audits to search

Summary: Add audit information to the commit search index.

Test Plan: Updated a commit, searched for terms in its comments, got hits.

Reviewers: btrahan, jungejason

Reviewed By: jungejason

CC: aran, epriestley

Maniphest Tasks: T904

Differential Revision: https://secure.phabricator.com/D1696