R1:35e7a1f3c073

Continue reducing callers to getCallsign()

Summary: Ref T4245. More of the same, just narrowing down the easy cases.

Test Plan:
- Called `diffusion.querycommit`.
- Browsed branches.
- Browsed repository.
- Browsed directory.
- Searched for stuff.
- Viewed a commit.
- Viewed a file diff.
- Edited a commit.
- Viewed history.
- Viewed tags.
- Viewed push log.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D14929