Don't unnecessary fetch error in is_callable()

As we just end up freeing it afterwards, avoid populating it in
the first place.

Author: nikic

ext/standard/type.c

@@ -402,7 +402,6 @@ PHP_FUNCTION(is_callable)
 {
 	zval *var, *callable_name = NULL;
 	zend_string *name;
-	char *error;
 	bool retval;
 	bool syntax_only = 0;
 	int check_flags = 0;
@@ -418,14 +417,10 @@ PHP_FUNCTION(is_callable)
 		check_flags |= IS_CALLABLE_CHECK_SYNTAX_ONLY;
 	}
 	if (ZEND_NUM_ARGS() > 2) {
-		retval = zend_is_callable_ex(var, NULL, check_flags, &name, NULL, &error);
+		retval = zend_is_callable_ex(var, NULL, check_flags, &name, NULL, NULL);
 		ZEND_TRY_ASSIGN_REF_STR(callable_name, name);
 	} else {
-		retval = zend_is_callable_ex(var, NULL, check_flags, NULL, NULL, &error);
-	}
-	if (error) {
-		/* ignore errors */
-		efree(error);
+		retval = zend_is_callable_ex(var, NULL, check_flags, NULL, NULL, NULL);
 	}
 
 	RETURN_BOOL(retval);