Improve the comment on stored_select_lock_type
ha_innodb.cc:
  Let InnoDB remember select_lock_type inside LOCK TABLES, also over plain consistent read SELECTs; fix Bug #5538 : assertion failure when using mysqldump with the -l option; in MERGING this patch to 4.1, there may be PROBLEMS; that is because previous patch was never merged to 4.1; Heikki Tuuri has to polish the code in 4.1 after this patch has been merged.