Stabilize sort in celerity map

Summary:
Smaller diffs, better blame, less noise on a file which is usually ignored.

Less conflicts in merge!

Test Plan: php -l __celerity_resource_map__.php

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D1909