Restore "avatar_url" field in User resource.

Review Request #8163 — Created May 15, 2016 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
09413fb...

Reviewers

The avatars work replaced the old avatar_url field with a new avatar_urls
field that has 1x, 2x, and maybe 3x resolutions. When this was done, rather
than deprecating the old field, it was removed. This change restores it and
marks it as deprecated.

Ran unit tests.