rabbitmq: enable/disable prometheus plugin follow up

Move new variables added in I4d694d6224c813285d228d6bc7eece5731db1078 to
role defaults.

Change-Id: Ie09a2dbae2701cb18fd1eb5bfab76e82f9920fb3

ansible/group_vars/all.yml

@@ -799,14 +799,6 @@ outward_rabbitmq_user: "openstack"
 rabbitmq_enable_tls: "no"
 # CA certificate bundle in RabbitMQ container.
 rabbitmq_cacert: "/etc/ssl/certs/{{ 'ca-certificates.crt' if kolla_base_distro in ['debian', 'ubuntu'] else 'ca-bundle.trust.crt' }}"
-rabbitmq_enable_prometheus_plugin: "{{ enable_prometheus }}"
-rabbitmq_plugins:
-  - name: "rabbitmq_management"
-    enabled: True
-  - name: "rabbitmq_prometheus"
-    enabled: "{{ rabbitmq_enable_prometheus_plugin | bool }}"
-
-rabbitmq_enabled_plugins: "{{ rabbitmq_plugins | selectattr('enabled', 'equalto', true) | list }}"
 
 ####################
 # Qdrouterd options

ansible/roles/rabbitmq/defaults/main.yml

@@ -90,3 +90,15 @@ rabbitmq_server_additional_erl_args: "+S 2:2 +sbwt none +sbwtdcpu none +sbwtdio
 rabbitmq_tls_options: {}
 # To avoid split-brain
 rabbitmq_cluster_partition_handling: "pause_minority"
+
+####################
+# Plugins
+####################
+rabbitmq_enable_prometheus_plugin: "{{ enable_prometheus }}"
+rabbitmq_plugins:
+  - name: "rabbitmq_management"
+    enabled: True
+  - name: "rabbitmq_prometheus"
+    enabled: "{{ rabbitmq_enable_prometheus_plugin | bool }}"
+
+rabbitmq_enabled_plugins: "{{ rabbitmq_plugins | selectattr('enabled', 'equalto', true) | list }}"