Pholio - upgrade herald effects to use transactions
Summary: Ref T4484
Test Plan: Made a mock. Made a herald rule to subscribe a user if mock had a string in title. Edited mock to have said string. Observed user subscribed correctly.
Reviewed By: epriestley
Subscribers: Korvin, epriestley
Maniphest Tasks: T4484
Differential Revision: https://secure.phabricator.com/D10725