Add http_listener input plugin to Telegraf

Change-Id: I34ad0668ad200018265cedb7b1cd3e1aa5bee093
Depends-On: I9afa5c93641a3b8c1a7403c553f30fb931d15057
diff --git a/telegraf/agent/init.yml b/telegraf/agent/init.yml
index 0e836e8..b1266b8 100644
--- a/telegraf/agent/init.yml
+++ b/telegraf/agent/init.yml
@@ -1,11 +1,4 @@
 classes:
 - service.telegraf.agent
-parameters:
-  telegraf:
-    agent:
-      output:
-        prometheus_client:
-          bind:
-            address: 0.0.0.0
-            port: 9126
-          engine: prometheus
+- service.telegraf.agent.output.prometheus_client
+- service.telegraf.agent.input.http_listener