view.

For Item_func_strcmp print() was not defined and for this class was called
print_op of it's parent class. Because of this strcmp() was printed wrongly
and this results int creation of broken view.

Added function Item_func_strcmp::print() which correctly prints strcmp()
function.


sql/item_cmpfunc.h:
  Fix bug #12489 wrongly printed strcmp() function results in creation of broken view.
mysql-test/r/view.result:
  Test case for bug #12489 wrongly printed strcmp() function results in creation of broken view.
mysql-test/t/view.test:
  Test case for bug #12489 wrongly printed strcmp() function results in creation of broken view.