Fix login tests that relied on settings.DEBUG.
Fix login tests that relied on settings.DEBUG.

Removing the override didn't break any of the affected tests and fixed
an issue with a test that relied on redirect login, so I did it!

MikkCZ/kitsune,MikkCZ/kitsune,MikkCZ/kitsune,brittanystoroz/kitsune,brittanystoroz/kitsune,mythmon/kitsune,mythmon/kitsune,mozilla/kitsune,brittanystoroz/kitsune,MikkCZ/kitsune,mozilla/kitsune,mythmon/kitsune,anushbmx/kitsune,anushbmx/kitsune,safwanrahman/kitsune,mozilla/kitsune,brittanystoroz/kitsune,anushbmx/kitsune,safwanrahman/kitsune,mythmon/kitsune,mozilla/kitsune,safwanrahman/kitsune,anushbmx/kitsune,safwanrahman/kitsune