The existing Audit code forgot to set authorPHID

Summary:
The audit tools has many false positive about Author Not
Matching with Revision. The fix is to set the authorPHID which was
missing in the existing code

Test Plan:
run reparse.php and it doesn't generate false positive result
anymore.

Reviewers: nh, epriestley

Reviewed By: epriestley

CC: aran

Differential Revision: https://secure.phabricator.com/D2119