R1:20a5c9b2618d

Use "closed", not "committed", in Differential

Summary: "Committed" is SVN-specific language, and confusing in Git and Mercurial. Use neutral language instead.

Test Plan: Inspection.

Reviewers: btrahan, Makinde, vrana, jungejason

Reviewed By: vrana

CC: aran

Maniphest Tasks: T909

Differential Revision: https://secure.phabricator.com/D2087