call err_clear in err_setval
diff --git a/Python/errors.c b/Python/errors.c
index 7266eca..7817108 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -72,11 +72,11 @@
 	object *exception;
 	object *value;
 {
-	XDECREF(last_exception);
+	err_clear();
+
 	XINCREF(exception);
 	last_exception = exception;
 	
-	XDECREF(last_exc_val);
 	XINCREF(value);
 	last_exc_val = value;
 }