R1:f748a472370f

strncmp is better than strpos

Summary: no need to get all O(N) up in this when we can do constant time of "8"

Test Plan: arc lint

Reviewers: vrana, epriestley

Reviewed By: vrana

CC: aran, Korvin

Maniphest Tasks: T891

Differential Revision: https://secure.phabricator.com/D3271