3fbd05078f
We generally expects that users enabled authentication both in Redis and Redis Sentinel at the same time, and it'd be more reasonable to use the same credential by default. This behavior is more consistent with the other libraries used in tooz or dogpile.cache, which are used in multiple OpenStack services. Change-Id: Ie8c96415f72bbd5f11f908bb9f96242d57b2bd4e