Fix openstack_api_check_status service name

Change-Id: Ia327b4085504d3e086360f4a46297bafdf0b44cd
diff --git a/nova/files/grafana_dashboards/nova_prometheus.json b/nova/files/grafana_dashboards/nova_prometheus.json
index 81c7c3a..be48d9d 100644
--- a/nova/files/grafana_dashboards/nova_prometheus.json
+++ b/nova/files/grafana_dashboards/nova_prometheus.json
@@ -69,7 +69,7 @@
           "tableColumn": "",
           "targets": [
             {
-              "expr": "min(openstack_api_check_status{service=~\"nova.api\"})",
+              "expr": "min(openstack_api_check_status{service=\"nova\"})",
               "format": "time_series",
               "intervalFactor": 2,
               "legendFormat": "{{ service }}",