Add 'datasource: influxdb' to Grafana meta

Change-Id: Ieddb5995f0bcf1358c1faba65bc7d3aa56321774
diff --git a/neutron/meta/grafana.yml b/neutron/meta/grafana.yml
index 5f68dcb..74c3432 100644
--- a/neutron/meta/grafana.yml
+++ b/neutron/meta/grafana.yml
@@ -1,5 +1,6 @@
 dashboard:
   service_level:
+    datasource: influxdb
     row:
       neutron-service-level:
         title: Neutron Service Levels
@@ -61,6 +62,7 @@
                 rawQuery: true
                 query: SELECT count(max) FROM openstack_neutron_http_response_times WHERE environment_label = '$environment' AND http_status = '5xx' AND $timeFilter
   main:
+    datasource: influxdb
     row:
       ost-control-plane:
         title: OpenStack Control Plane