Fix code not working in HHVM

Summary:
It's also more readable so I think it's OK.
I've also filed a bug for HHVM.

Test Plan: arc unit in HHVM

Reviewers: epriestley, jungejason

Reviewed By: jungejason

CC: aran, Koolvin

Differential Revision: https://secure.phabricator.com/D2551