Fix running the Review Board test suite using `manage.py test`.
Review Request #8171 — Created May 17, 2016 and submitted
The recent work to add modern Pipeline support needed to make use of the flags we had for determining if we're running unit tests, and therefore needed to move that state setting out of the test runner class and into the actual test script being executed. The necessary change was made to tests/runtests.py, but manage.py never got the fix. We now set the RB_RUNNING_TESTS environment variable in manage.py if we know we're running the test suite, enabling this script to be used reliably once again.
Unit tests run with manage.py.
Tool: Pyflakes Processed Files: reviewboard/manage.py Tool: PEP8 Style Checker Processed Files: reviewboard/manage.py