This ChangeSet will be null-merged to mysql-5.1.

Bugs fixed:
- Bug #21638:  InnoDB: possible segfault in page_copy_rec_list_end_no_locks
  If prefix_len is specified, write it to the insert buffer instead of type->len
- bug #10746:  InnoDB: Error: stored_select_lock_type is 0 inside ::start_stmt()!
  INSERT ... SELECT uses LOCK_NONE in innodb_locks_unsafe_for_binlog mode, so do
  not check for LOCK_X or LOCK_S in start_stmt()