Fix Contrail API status

Change-Id: I8e219c0c12dec964bd05603f8c62d1cbf5856259
diff --git a/opencontrail/files/grafana_dashboards/contrail_prometheus.json b/opencontrail/files/grafana_dashboards/contrail_prometheus.json
index 2f7a9ce..c509a64 100644
--- a/opencontrail/files/grafana_dashboards/contrail_prometheus.json
+++ b/opencontrail/files/grafana_dashboards/contrail_prometheus.json
@@ -46,7 +46,7 @@
           "steppedLine": false,
           "targets": [
             {
-              "expr": "max(http_response_status{host=~\"$host\",service=\"contrail.api\",host=~\"$host\"}) by (host)",
+              "expr": "max(http_response_status{host=~\"$host\",service=~\"contrail.api\",host=~\"$host\"}) by (host)",
               "format": "time_series",
               "intervalFactor": 2,
               "legendFormat": "{{ host }}",