mysql-test/r/func_str.result:
  Fix for bug #12728: Very strange behaviour of ELT
    - test case
mysql-test/t/func_str.test:
  Fix for bug #12728: Very strange behaviour of ELT
    - test result
sql/item_strfunc.cc:
  Fix for bug #12728: Very strange behaviour of ELT
    - Item_func_elt::eq() introduced: check 'item' member as well
      (to distinguish for instance elt(1, 'a', 'b') and elt(2, 'a', 'b')
sql/item_strfunc.h:
  Fix for bug #12728: Very strange behaviour of ELT
    - Item_func_elt::eq() introduced: check 'item' member as well
      (to distinguish for instance elt(1, 'a', 'b') and elt(2, 'a', 'b')