Avoid resolving path in celerity resource map
Summary:
HPHP doesn't like resolved symlinks.
Also I like this code better.
Test Plan: Used and not used custom Celerity map.
Reviewers: epriestley, nh
Reviewed By: epriestley
CC: aran, Korvin
Differential Revision: https://secure.phabricator.com/D2694