Fix inconsistent default notification driver

Use the os_service_default fact, which effectively means noop
notification driver, because it is a more commonly used default.

Closes-Bug: #2079986
Change-Id: Ia0d3fcf2b4a951144a4c03732f5a637e40c68aeb

manifests/init.pp

@@ -42,7 +42,7 @@
 #
 # [*notification_driver*]
 #   (optional) Driver or drivers to handle sending notifications.
-#   Defaults to 'messaging'
+#   Default to $facts['os_service_default']
 #
 # [*rabbit_ha_queues*]
 #   (optional) Use HA queues in RabbitMQ (x-ha-policy: all).
@@ -172,7 +172,7 @@ class manila (
   $control_exchange                = $facts['os_service_default'],
   $executor_thread_pool_size       = $facts['os_service_default'],
   $notification_transport_url      = $facts['os_service_default'],
-  $notification_driver             = 'messaging',
+  $notification_driver             = $facts['os_service_default'],
   $notification_topics             = $facts['os_service_default'],
   $rabbit_ha_queues                = $facts['os_service_default'],
   $rabbit_quorum_queue             = $facts['os_service_default'],

releasenotes/notes/bug-2079986-6ec7172fb10d836b.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    The ``manila::notification_driver`` parameter now defaults to
+    the os_service_default fact, which is the default value more globally used
+    by the other Puppet OpenStack modules. Set the parameter to ``messaging``
+    to keep using the previous default value.

spec/classes/manila_init_spec.rb

@@ -29,7 +29,7 @@ describe 'manila' do
         )
         is_expected.to contain_oslo__messaging__notifications('manila_config').with(
           :transport_url => '<SERVICE DEFAULT>',
-          :driver        => 'messaging',
+          :driver        => '<SERVICE DEFAULT>',
           :topics        => '<SERVICE DEFAULT>',
         )
         is_expected.to contain_oslo__messaging__rabbit('manila_config').with(
@@ -192,6 +192,8 @@ describe 'manila' do
           :rpc_response_timeout       => '120',
           :control_exchange           => 'manila',
           :notification_transport_url => 'rabbit://rabbit_user:password@localhost:5673',
+          :notification_driver        => 'messagingv2',
+          :notification_topics        => ['notifications'],
           :executor_thread_pool_size  => 64,
         }
       end
@@ -204,7 +206,9 @@ describe 'manila' do
       ) }
 
       it { is_expected.to contain_oslo__messaging__notifications('manila_config').with(
-        :transport_url => 'rabbit://rabbit_user:password@localhost:5673'
+        :transport_url => 'rabbit://rabbit_user:password@localhost:5673',
+        :driver        => 'messagingv2',
+        :topics        => ['notifications']
       ) }
     end
   end