objexcept: Fix another place missing proper args tuple initialization.
diff --git a/py/objexcept.c b/py/objexcept.c
index 6f2a3f0..afcaa1c 100644
--- a/py/objexcept.c
+++ b/py/objexcept.c
@@ -205,6 +205,7 @@
     mp_obj_exception_t *o = m_new_obj_var(mp_obj_exception_t, mp_obj_t, 0);
     o->base.type = exc_type;
     o->traceback = MP_OBJ_NULL;
+    o->args.base.type = &mp_type_tuple;
     o->args.len = 0;
 
     if (fmt == NULL) {