R1:9358b08b4604

Use "Diff <id>" instead of "D<id>" in changeset view

Summary: We use "D<id>" for revisions.

Test Plan: Looked at revision.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D4258