Add prometheus_client class to system.telegraf.agent

Change-Id: I1fcf0204ab8ea08b1bf179fe3be0914f6a24e327
diff --git a/telegraf/agent/init.yml b/telegraf/agent/init.yml
index ca7e2b0..64ef566 100644
--- a/telegraf/agent/init.yml
+++ b/telegraf/agent/init.yml
@@ -1,13 +1,5 @@
 classes:
 - service.telegraf.agent
 - system.telegraf.agent.input.http_listener
+- system.telegraf.agent.output.prometheus_client
 - system.telegraf.sudo
-parameters:
-  telegraf:
-    agent:
-      output:
-        prometheus_client:
-          bind:
-            address: 0.0.0.0
-            port: 9126
-          engine: prometheus