- Wrong thd uses in Item_subselect, could lead to crash
- Inititalize uninitialized variable in new autoincrement handling code


sql/handler.cc:
  More DBUG_PRINT
sql/item_subselect.cc:
  Wrong thd uses in Item_subselect, could lead to crash
storage/innobase/handler/ha_innodb.cc:
  Initialize variable needed by upper level. This only happens when auto-increment value wraps over.
storage/xtradb/handler/ha_innodb.cc:
  Initialize variable needed by upper level. This only happens when auto-increment value wraps over.