[BUG] Phalcon\Config::offsetUnset() does not work

[ghost]

Test case:

$x = new Phalcon\Config(array('a' => 0));
echo $x['a'], "\n";
unset($x['a']);
echo $x['a'], "\n";

Actual result:

0
0

Expected result:

0
PHP Notice:  Undefined property: Phalcon\Config::$a

[ghost]

The only idea that comes to mind is

@@ -309,6 +309,11 @@ PHP_METHOD(Phalcon_Config, offsetUnset){
        zval *index;

        phalcon_fetch_params(0, 1, 0, &index);
+#if PHP_VERSION_ID < 50400
+       Z_OBJ_HANDLER_P(getThis(), unset_property)(getThis(), index TSRMLS_CC);
+#else
+       Z_OBJ_HANDLER_P(getThis(), unset_property)(getThis(), index, 0 TSRMLS_CC);
+#endif

        RETURN_TRUE;
 }