Fix transaction errors when running review group tests

Review Request #9177 — Created Sept. 7, 2017 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
4f2a4a4...

Reviewers

When running unit tests, if an IntegrityError error is raised (even if
it is caught), it will break the transaction the unit test runs in.
Therefore, we have to run the potentially exception-raising code in its
own atomic block to avoid this happening.

This also changes a mistaken reference to self.self.local_site_name.

Ran unit tests.