R1:c821639e93d5

Opt-in approve your own Differential revisions

Summary: Did exactly what @epriestley suggested in T1428#2.

Test Plan: Turn it on in your config, post a revision, accept it. Turn it off in your config, post a revision, can't accept it.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D2900