Use SettingsOverride(…) for cache test

Signed-off-by: Martin Koistinen <mkoistinen@gmail.com>
Merge pull request #2772 from mkoistinen/cache_tests_with_settings_override

Use SettingsOverride(…) for cache test
Shame on me, remove leftover print
Merge pull request #2774 from yakky/feature/fix_leftover

Shame on me, remove leftover print
Merge branch 'develop' of https://github.com/divio/django-cms into issue_2213
Just delete unneeded import.

Signed-off-by: Martin Koistinen <mkoistinen@gmail.com>