Fixed bug #10982.
item.cc:
  Fixed bug #10982. In the function Item_ref::val_decimal
  by mistake the method Item_ref::val_decimal was used
  instead of Item_ref::val_decimal_result.


sql/item.cc:
  Fixed bug #10982. In the function Item_ref::val_decimal
  by mistake the method Item_ref::val_decimal was used
  instead of Item_ref::val_decimal_result.
mysql-test/r/olap.result:
  Fixed bug #10982.