Add stacklight_environment parameter

This allows Nagios to support several environments.

https://github.com/Mirantis/mk-lab-salt-model/pull/197
diff --git a/heka/remote_collector/cluster.yml b/heka/remote_collector/cluster.yml
index 13dffe0..3da60c1 100644
--- a/heka/remote_collector/cluster.yml
+++ b/heka/remote_collector/cluster.yml
@@ -1,5 +1,6 @@
 classes:
 - service.heka.remote_collector.cluster
+- system.heka.server
 parameters:
   heka:
     remote_collector: