Add service validation to Patrole framework

Verify that the service being passed in the rbac_rule_validation
decorator is a valid service. The Tempest Identity v3 services_client
is being used to make a call to Keystone to list the services that
are available.

If an invalid service is passed in the decorator, then an exception
is thrown.

Change-Id: I3de3fccf18456bb8382864eeabcbfe64e2cffebb
Implements: blueprint add-service-validation
4 files changed