Remove out-of-date configurations in setup.cfg
Remove out-of-date configurations in setup.cfg

We add the oslo_messaging.notify.drivers configuration in [1] for
backwards compat with Havana notification_driver configuration values,
and add the oslo_middleware configuration in [2] for backwards
compatibility with Juno middleware configurations.

But now these configuration is already out-of-date and useless, so we
remove these configurations in this patch.

[1] bcd9f363ff8a10ff30795c54f471a8c6d76450fe
[2] c4897471777949983912676ad46ad99c42ed2b22

Change-Id: I92792a98bb21e2759549949333dba82df4345c01

mahak/cinder,openstack/cinder,mahak/cinder,openstack/cinder