Summary: I broke this when converting to PhabricatorUserEditor.
Test Plan:
Ran `accountadmin`, created an admin account, verified the "new value" column showed "Y".
ACCOUNT SUMMARY
OLD VALUE NEW VALUE
Username derp
Real Name derprp
Email derp@derp.com
Password Unchanged
Admin N Y
Reviewers: btrahan, nikil
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T1434
Differential Revision: https://secure.phabricator.com/D2908