Comment 5 for bug 1446078

I think this is the limitation of apache wsgi.
Apache log level is not referred to in WSGI application (horizon in this case). Logging level of WSGI application needs to be configured separately.

My suggestions are:
- Configure Django logging depending on your desired log level https://docs.djangoproject.com/en/2.0/topics/logging/
- Use '%(levelname)s %(name)s %(message)s' as Django log format
- Use ErrorLogFormat "%{cu}t %M" for Apache logging