Abuse of CONF.keymgr.encryption_auth_url in quota

CONF.keymgr.encryption_auth_url is used in quota code, which is not related to keymgr.

https://github.com/openstack/cinder/blob/71355fdbadb8155743350a182778fe87f0f64e8a/cinder/api/contrib/quotas.py#L183

    def _get_project(self, context, id, subtree_as_ids=False):
        """A Helper method to get the project hierarchy.
        Along with Hierachical Multitenancy, projects can be hierarchically
        organized. Therefore, we need to know the project hierarchy, if any, in
        order to do quota operations properly.
        """
        try:
            keystone = client.Client(auth_url=CONF.keymgr.encryption_auth_url, # <= this
                                     token=context.auth_token,
                                     project_id=context.project_id)
            project = keystone.projects.get(id, subtree_as_ids=subtree_as_ids)
        except exceptions.NotFound:
            msg = (_("Tenant ID: %s does not exist.") % id)
            raise webob.exc.HTTPNotFound(explanation=msg)
        return project

In addition, this usage of keystoneclient will make two request to keystone. The first request to fetch catalog, the second one to get the project. It is inefficient, especially when multiple regions and identity endpoints are listed in the catalog and keystoneclient selects one that is distant from the cinder. It seems that we can pass the "endpoint" parameter instead of the "auth_url" parameter to keystoneclient so that only one request is sent to a specified (nearest) identity endpoint.