Lots of fixes to do this.
- setup_celery_from_config no longer responsible for checking
'celery_setup_elsewhere'; that's the app's job. (This was a problem
because more than the app was relying on using this function)
- Allow us to specifically set the config file we're setting up
celery from with setup_self
- Set up celery_always_eager. This is something we strongly want
while doing tests.
- Instead of setting up the app in the get_test_app method, let's set
that up simply by importing from_tests, which should itself up via
from_celery being the environment variable being set.
9ea5c28b7a