str and unicode objects now have a __mod__ slot so don't special case them in

PyNumber_Remainder().  This fixes SF bug #615506 and allows string and unicode
subclasses to override __mod__.

Objects/abstract.c

@@ -639,12 +639,6 @@ PyNumber_TrueDivide(PyObject *v, PyObject *w)
 PyObject *
 PyNumber_Remainder(PyObject *v, PyObject *w)
 {
-	if (PyString_Check(v))
-		return PyString_Format(v, w);
-#ifdef Py_USING_UNICODE
-	else if (PyUnicode_Check(v))
-		return PyUnicode_Format(v, w);
-#endif
 	return binary_op(v, w, NB_SLOT(nb_remainder), "%");
 }