Don't reset message if missing Room Title in New Conpherence Room

Summary: Fixes T9000, sets a variable.

Test Plan: Try to make a new room without a title, but with a message.

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T9000

Differential Revision: https://secure.phabricator.com/D13754