Grafana post_config checks only need to run locally

Recently added post_config for Grafana does some uri queries,
these can be problematic if run across every node.

Change-Id: I580212474879da18780fc5f66a21952a9e6f8daa

ansible/roles/grafana/tasks/post_config.yml

@@ -6,7 +6,7 @@
 
 - name: Enable influxdb datasource
   uri:
-    url: "{{ internal_protocol }}://{{ api_interface_address }}:{{ grafana_server_port }}/api/datasources"
+    url: "{{ internal_protocol }}://{{ kolla_internal_vip_address }}:{{ grafana_server_port }}/api/datasources"
     method: POST
     user: admin
     password: "{{ grafana_admin_password }}"
@@ -15,6 +15,8 @@
     force_basic_auth: yes
     status_code: 200, 409
   register: response
+  run_once: True
+  connection: local
   when: grafana_data_source is defined
   changed_when: response.status == 200
   failed_when: response.status not in [200, 409] or