The Magnum service allow enables policies (RBAC) new defaults and scope by
default. The Default value of config options ``[oslo_policy] enforce_scope``
and ``[oslo_policy] oslo_policy.enforce_new_defaults`` are both to
``False``, but will change to ``True`` in following cycles.

To enable them then modify the below config options value in
``magnum.conf`` file::

  [oslo_policy]
  enforce_new_defaults=True
  enforce_scope=True

reference tc goal for more detail:
https://governance.openstack.org/tc/goals/selected/consistent-and-secure-rbac.html

Related blueprint secure-rbac

Change-Id: I249942a355577c4f1ef51b3988f0cc4979959d0b