Rich comparisons fallout: PyObject_Hash() should check for both

tp_compare and tp_richcompare NULL before deciding to do a quickie
based on the object address.  (Tim Peters discovered this.)

Objects/object.c

@@ -914,7 +914,7 @@ PyObject_Hash(PyObject *v)
 	PyTypeObject *tp = v->ob_type;
 	if (tp->tp_hash != NULL)
 		return (*tp->tp_hash)(v);
-	if (tp->tp_compare == NULL) {
+	if (tp->tp_compare == NULL && tp->tp_richcompare == NULL) {
 		return _Py_HashPointer(v); /* Use address as hash value */
 	}
 	/* If there's a cmp but no hash defined, the object can't be hashed */