Fix PhabricatorPolicyDataTestCase
Summary: Fixes T5219.
Test Plan: Ran arc unit.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: epriestley, Korvin
Maniphest Tasks: T5219
Differential Revision: https://secure.phabricator.com/D9326