Fix an exception in Ponder comment saving.

Summary:
Add a setViewer() so that PHID loading doesn't throw.

Also remove a period from a button because none of the others have one.

Test Plan: Saved a comment successfully.

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4202