Use 'openstack' in Grafana dashboard tags

Change-Id: I2b7612a752d06d394870251ed8faea10356d5611
Related-Bug: PROD-17781
diff --git a/cinder/files/grafana_dashboards/cinder_prometheus.json b/cinder/files/grafana_dashboards/cinder_prometheus.json
index ed1f67d..0995705 100644
--- a/cinder/files/grafana_dashboards/cinder_prometheus.json
+++ b/cinder/files/grafana_dashboards/cinder_prometheus.json
@@ -2327,7 +2327,7 @@
   "sharedCrosshair": true,
   "style": "dark",
   "tags": [
-    "cinder"
+    "openstack"
   ],
   "templating": {
     "list": [
diff --git a/cinder/files/grafana_dashboards/cinder_prometheus_fluentd.json b/cinder/files/grafana_dashboards/cinder_prometheus_fluentd.json
index 6c6561f..1146795 100644
--- a/cinder/files/grafana_dashboards/cinder_prometheus_fluentd.json
+++ b/cinder/files/grafana_dashboards/cinder_prometheus_fluentd.json
@@ -2327,7 +2327,7 @@
   "sharedCrosshair": true,
   "style": "dark",
   "tags": [
-    "cinder"
+    "openstack"
   ],
   "templating": {
     "list": [