Prune not used namespaces.

Summary:
Log class is now only called from GateController, not the children.

This is a follow-up of D219 / rNOTIFcc622917e76d.

Test Plan: tail -f storage/logs/laravel.log && phpunit --no-coverage

Reviewers: dereckson

Subscribers: alken-orin

Differential Revision: http://devcentral.nasqueron.org/D220