Always install JX.log, even in production

Summary:
Ref T5366. Currently, enabling notification.debug fails to produce any messages unless developer mode is also enabled.

There's no reason we need to disable JX.log in production, and the byte size of the method is very small. Always provide a real JX.log implementation.

Test Plan: Saw notification debugging without needing to enable developer mode.

Reviewers: btrahan, joshuaspence, hach-que

Reviewed By: hach-que

Subscribers: epriestley

Maniphest Tasks: T5366

Differential Revision: https://secure.phabricator.com/D10104