R1:b9cf9e6f0db9

Fix an issue with PHID/handle management in push logs

Summary: Ref T10751. This cleans this up so it's a little more modern, and fixes a possible bad access on the log detail page.

Test Plan: Viewed push log list, viewed push log detail.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10751

Differential Revision: https://secure.phabricator.com/D15765