Summary: Fixes T3566 List of poll actions should include ability to close an open poll or reopen a closed poll.
Test Plan: Poll author should be able to close/reopen poll. Non-author should get policy screen when attempting to close/reopen poll.
Reviewers: epriestley, #blessed_reviewers
Reviewed By: epriestley, #blessed_reviewers
Subscribers: epriestley, Korvin
Maniphest Tasks: T3566
Differential Revision: https://secure.phabricator.com/D8846
