R1:140927926d20

Use a join instead of an awkward, weird query in PhabricatorAuditListController

Summary:
- Use a join to effect this query.
- Fixes a bug where packages with no commits would raise an exception because of the awkward query construction.
- Fixes a bug on audit views.

Test Plan:
- Viewed a package with no commits.
- Altered audit filters.

Reviewers: btrahan, 20after4

Reviewed By: 20after4

CC: aran, epriestley

Maniphest Tasks: T904

Differential Revision: https://secure.phabricator.com/D1801