Fix test_page_menu_defaults side effects

Two unrelated test fixes I've run into in my [attempt at the 1.8 ``DiscoverRunner``](https://github.com/wrwrwr/mezzanine/compare/maintenance/1.8-discover-test-runner) (maybe to be properly announced some day, maybe not, considering how patchy, even after two rewrites, it turned out).

If you've ever wondered about some mysterious ``pages_p1`` table missing, I'm the one to blame.