rli->save_temporary_tables and slave_open_temp_tables
(in old 4.0 you could make "SHOW STATUS LIKE 'slave_open_temp_tables'" grow
indefinitely by doing RESET SLAVE and replicating always the same CREATE
TEMPORARY TABLE).
It's critical to reset save_temporary_tables to 0 (otherwise you may later
read memory which has been freed) so this changeset should go into 4.1.