Since 3.7.0, oslo policy started the DeprecationWarning[1] if
deprecated_reason and deprecated_since param are not passed
in DeprecatedRule or they are passed in RuleDefault object.
These warnings are logged for every test which increase the
log size and sometime can full the log buffer and fail the
job.
[1] https://github.com/openstack/oslo.policy/blob/3.7.0/oslo_policy/policy.py#L1538
Change-Id: I5f7b2027e9d015cef6e8e7b459ebf2005c432209