Use PhabricatorAuditEditor to write revert edges

Summary: Use PhabricatorAuditEditor instead of PhabricatorEdgeEditor when writing reverts edges. This ensures that a transaction is created in addition to the edge.

Test Plan: Reverted a commit and pushed to remote. Saw a row created in phabricator_audit.audit_transaction_comment. Interestingly, I can't actually see the transaction at http://phabricator.local/r${CALLSIGN}${REVERTED_COMMIT_HASH}.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D11212