Tidy paths for require_once

Summary: Use .. instead of dirname(). I think that this is much neater.

Test Plan: Ran all of the affected scripts.

Reviewers: epriestley, Blessed Reviewers

Reviewed By: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9969