Summary: T5549
Test Plan: Set edit policy on paste, check that only users meeting the policy requirements can edit it.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: Korvin, epriestley
Maniphest Tasks: T5549
Differential Revision: https://secure.phabricator.com/D11097
