Minor docstring update

src/reactive/designate_bind_handlers.py

@@ -89,5 +89,6 @@ def check_zone_status(hacluster):
 @reactive.when('zones.initialised')
 @reactive.when('cluster.connected')
 def process_sync_requests(hacluster):
+    '''If this unit is the leader process and new sync requests'''
     if hookenv.is_leader():
         designate_bind.process_requests(hacluster)