Add missing class to sl_k8s_calico model

Change-Id: I2905c8c182ba4c6020b33eeeda51ac4b52062a45
diff --git a/classes/cluster/sl_k8s_calico/stacklight/server.yml b/classes/cluster/sl_k8s_calico/stacklight/server.yml
index 8426444..7eafd54 100644
--- a/classes/cluster/sl_k8s_calico/stacklight/server.yml
+++ b/classes/cluster/sl_k8s_calico/stacklight/server.yml
@@ -32,6 +32,7 @@
 - system.docker.swarm.stack.monitoring
 - system.docker.swarm.stack.dashboard
 - system.docker.swarm.stack.monitoring.remote_collector
+- system.heka.ceilometer_collector.single
 - cluster.sl_k8s_calico
 parameters:
   _param: