Add support for prometheus

Change-Id: I09d4c436d7abf7bfe0102e4b9f5ca55b85094733
diff --git a/metadata/service/support.yml b/metadata/service/support.yml
index d3840ab..5d63b97 100644
--- a/metadata/service/support.yml
+++ b/metadata/service/support.yml
@@ -1,6 +1,8 @@
 parameters:
   etcd:
     _support:
+      prometheus:
+        enabled: true
       collectd:
         enabled: true
       heka: