Fix a couple of minor OAuthServer things

Summary:
I was a bit hasty with this.

• This should be uninstallable.
• Provide a real description.
• Choose a better title glyph (trident of neptune).

Test Plan: Poked around.

Reviewers: btrahan, chad

Reviewed By: chad

Subscribers: aran, epriestley

Differential Revision: https://secure.phabricator.com/D8534