Ensure per-resource caches work without global cache
Ensure per-resource caches work without global cache

With the move to dogpile based per-resource caches, we need to make sure
they still exist if they are configured, even if global cache isn't. To
do this, test to see if any are set, and if so, configure the global to
be FakeCache but the per-resource to be memory cache.

Change-Id: I8261b807352a4b54b19f6831b795eedc847e86ab

openstack-infra/shade,dtroyer/python-openstacksdk,openstack/python-openstacksdk,openstack-infra/shade,openstack/python-openstacksdk,stackforge/python-openstacksdk,dtroyer/python-openstacksdk,stackforge/python-openstacksdk