Updated openstack/openstack
Project: openstack/keystone  c9d28a3ed2f75ffb0bb2a34065db305a8a762255

Remove unused cache functions from token.core

With the move of functionality from token.core to token.persistence
the cache functions and import are no longer needed in token.core.

Change-Id: I97c96fff64b5c952155c4054df05b1b3ec3a83c5