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()


innobase/ibuf/ibuf0ibuf.c:
  Applied innodb snapshot ss792 and ss854.
  
  ibuf_entry_build(): Write prefix_len to the insert buffer instead of type->len
  when prefix_len is specified.  Otherwise, btr_page_reorganize() during
  insert buffer merge would fail on ROW_FORMAT=COMPACT tables.  (Bug #21638)
innobase/include/data0type.h:
  Applied innodb snapshot ss792 and ss854.
  
  ibuf_entry_build(): Write prefix_len to the insert buffer instead of type->len
  when prefix_len is specified.  Otherwise, btr_page_reorganize() during
  insert buffer merge would fail on ROW_FORMAT=COMPACT tables.  (Bug #21638)
innobase/include/data0type.ic:
  Applied innodb snapshot ss792 and ss854.
  
  ibuf_entry_build(): Write prefix_len to the insert buffer instead of type->len
  when prefix_len is specified.  Otherwise, btr_page_reorganize() during
  insert buffer merge would fail on ROW_FORMAT=COMPACT tables.  (Bug #21638)
sql/ha_innodb.cc:
  Applied innodb snapshot ss792 and ss854.
  
  ha_innobase::start_stmt(): Remove the check for
  prebuilt->stored_select_lock_type being LOCK_X or LOCK_S.
  This would cause false alarms with INSERT ... SELECT, which would use
  LOCK_NONE in innodb_locks_unsafe_for_binlog mode.  (Bug #10746)