Pass REDIS connection as an URL to django-redis-session

[noliveleger]

@bufke said:

SESSION_REDIS is being set to

{'BACKEND': 'django_redis.cache.RedisCache', 'LOCATION': 'redis://:xxxxxx@redis-cache.kobo.private:6380/2'}

which is right for built in django things...but not django-redis-sessions. It wants {'host': 'host', 'port': '6379', 'db': '1', 'password': '', 'prefix': 'session', 'socket_timeout': 1}

[bufke]

This retains the LOCATION and ENGINE in the dict which aren't used by SESSION_REDIS. If for some reason there was ever a collision of values, it could introduce expected errors. I'd prefer to make a new dict instead of merging.