R1:0e7049e8aafc

Countdown - kill tabs

Summary: pretty simple stuff here. "View" controller had a 'view' tab selected
which DNE.

Test Plan: viewed countdown, noted no tabs

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, epriestley

Maniphest Tasks: T631

Differential Revision: 1222