Fix Zookeeper alert

Change-Id: Ia4b394f99b20ff8bc530eee8ef0f40086ce6cd34
diff --git a/opencontrail/meta/prometheus.yml b/opencontrail/meta/prometheus.yml
index 6f86598..2bc47ce 100644
--- a/opencontrail/meta/prometheus.yml
+++ b/opencontrail/meta/prometheus.yml
@@ -506,7 +506,7 @@
         service: zookeeper
       annotations:
         summary: 'Zookeeper service down'
-        description: 'Zookeeper service is down on node {{ $labels.host }}.'
+        description: 'Zookeeper service is down on node {% raw %}{{ $labels.host }}{% endraw %}.'
     {%- endif %}
 
     {%- if exporters is defined %}