Enable Prometheus endpoint for Calico

Change-Id: I5c4166b21aaef9de4a7eb11325958d0f93d6cbe6
diff --git a/kubernetes/master/cluster.yml b/kubernetes/master/cluster.yml
index 0539331..ab283d0 100644
--- a/kubernetes/master/cluster.yml
+++ b/kubernetes/master/cluster.yml
@@ -9,4 +9,6 @@
       container: false
       network:
         engine: calico
-        private_ip_range: ${_param:calico_private_network}/${_param:calico_private_netmask}
\ No newline at end of file
+        private_ip_range: ${_param:calico_private_network}/${_param:calico_private_netmask}
+        prometheus:
+          enabled: true