Fix account page tests.
Review Request #6211 — Created Aug. 8, 2014 and submitted
The addition of the API tokens page for the user account preferences caused
some test breakages. I've fixed them, and also centralized the code a bit so
there are fewer changes to make when we change the structure of the pages.
Ran unit tests.
Tool: Pyflakes Processed Files: reviewboard/accounts/tests.py Tool: PEP8 Style Checker Processed Files: reviewboard/accounts/tests.py