Replace remote-sink description with valid example

Remote sync configures ceilometer.event.publisher. Only a subset of
    publishers are valid.  They are test, messaging, http, gnocchi and
    zaqar

Change-Id: I56028d674eae58d224ee843152623bdb0d2b5d45

config.yaml

@@ -254,11 +254,11 @@ options:
     default:
     description: |
       Space delimited list of remote consumers of Ceilometer event reporting
-      which reside outside of the deployed model. Only supported for Mitaka
-      and later clouds. e.g.
+      which reside outside of the deployed model. Valid remotes are test, 
+      messaging, http and gnocchi. e.g.
       .
-      'udp://<host>:<port>/'
-      'prometheus://pushgateway-host:9091/metrics/job/openstack-telemetry'
+      'http://host:80/path?timeout=1&max_retries=2&batch=False'
+      'gnocchi://host:8041?archive_policy=low&filter_project=gnocchi'
   pipeline-yaml:
     type: string
     default: ""