Drop old notification driver names

These were added in Havana cycle to keep compatibility during migration
to oslo.messaging[1]. Since multiple cycles have passed and we can now
expect users are using oslo.messaging drivers instead of these
deprecated names, we now remove these ancient treatment.

The same removal has already been done in other projects such as Nova
or Cinder.

[1] 8e5da48361333d2cafc6ded6e6195cb085d90913

Change-Id: Ib7080947cdefbf04cb1a169de19c67ccd803d458

releasenotes/notes/remove-old-notif-drivers-ea9f3837c8e82a41.yaml

@@ -0,0 +1,11 @@
+---
+upgrade:
+  - |
+    The following aliases of notification drivers are no longer available. Use
+    the driver names in the ``oslo.messaging`` library instead.
+
+    - ``manila.openstack.common.notifier.log_notifier``
+    - ``manila.openstack.common.notifier.no_op_notifier``
+    - ``manila.openstack.common.notifier.rpc_notifier``
+    - ``manila.openstack.common.notifier.rpc_notifier2``
+    - ``manila.openstack.common.notifier.test_notifier``

setup.cfg

@@ -66,13 +66,6 @@ manila.scheduler.weighers =
     PoolWeigher = manila.scheduler.weighers.pool:PoolWeigher
     HostAffinityWeigher = manila.scheduler.weighers.host_affinity:HostAffinityWeigher
 
-# These are for backwards compat with Havana notification_driver configuration values
-oslo_messaging.notify.drivers =
-    manila.openstack.common.notifier.log_notifier = oslo_messaging.notify._impl_log:LogDriver
-    manila.openstack.common.notifier.no_op_notifier = oslo_messaging.notify._impl_noop:NoOpDriver
-    manila.openstack.common.notifier.rpc_notifier2 = oslo_messaging.notify.messaging:MessagingV2Driver
-    manila.openstack.common.notifier.rpc_notifier = oslo_messaging.notify.messaging:MessagingDriver
-    manila.openstack.common.notifier.test_notifier = oslo_messaging.notify._impl_test:TestDriver
 oslo.config.opts =
     manila = manila.opts:list_opts
 oslo.config.opts.defaults =