Fix bug #12489 wrongly printed strcmp() function results in creation of broken

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.

mysql-test/r/view.result

@@ -2135,3 +2135,9 @@ DESCRIBE v1;
 ERROR HY000: View 'test.v1' references invalid table(s) or column(s) or function(s)
 DROP TABLE t1;
 DROP VIEW v1;
+create table t1 (f1 char);
+create view v1 as select strcmp(f1,'a') from t1;
+select * from v1;
+strcmp(f1,'a')
+drop view v1;
+drop table t1;

mysql-test/t/view.test

@@ -1995,3 +1995,12 @@ ALTER TABLE t1 CHANGE COLUMN f4 f4x CHAR(5);
 DESCRIBE v1;
 DROP TABLE t1;
 DROP VIEW v1;
+
+# 
+# Bug #12489 wrongly printed strcmp() function results in creation of broken
+#            view
+create table t1 (f1 char);
+create view v1 as select strcmp(f1,'a') from t1;
+select * from v1;
+drop view v1;
+drop table t1;

sql/item_cmpfunc.h

@@ -427,6 +427,7 @@ public:
   longlong val_int();
   optimize_type select_optimize() const { return OPTIMIZE_NONE; }
   const char *func_name() const { return "strcmp"; }
+  void print(String *str) { Item_func::print(str); }
 };