Remove warning message for old change

This removes the warning message added to inform the old change which
was merged multiple cycles ago[1], because we can safely assume users
are aware of this change.

[1] 3c08645ba8

Change-Id: Ifca8a60409093b31f780c6a47a9cce0f9635286e

manifests/init.pp

@@ -627,11 +627,8 @@ Support for deploying under eventlet will be dropped as of the M-release of Open
 running as a standalone service, or httpd for being run by a httpd server")
       }
     }
-  } else {
-    warning('Execution of db_sync does not depend on $enabled anymore. Please use sync_db instead.')
   }
 
-
   if $sync_db {
     include keystone::db::sync
   }