Update connection.rst (elastic#768)

Changed parameter name

Author: dchimeno

docs/connection.rst

@@ -24,7 +24,7 @@ For example if you wanted to use your own implementation of the
 Transport
 ---------
 
-.. autoclass:: Transport(hosts, connection_class=Urllib3HttpConnection, connection_pool_class=ConnectionPool, nodes_to_host_callback=construct_hosts_list, sniff_on_start=False, sniffer_timeout=None, sniff_on_connection_fail=False, serializer=JSONSerializer(), max_retries=3, ** kwargs)
+.. autoclass:: Transport(hosts, connection_class=Urllib3HttpConnection, connection_pool_class=ConnectionPool, host_info_callback=construct_hosts_list, sniff_on_start=False, sniffer_timeout=None, sniff_on_connection_fail=False, serializer=JSONSerializer(), max_retries=3, ** kwargs)
  :members: