Updates hydra: 9d73ff3 Fixes for aperiodic-upgrade

diff --git a/hydra b/hydra
index 71784150d00655e8ebfb65026ea97e2d9dd6fb68..9d73ff39c0d2c43ab9799ea824698b4f7424c7b8 160000 (submodule)
--- a/hydra
+++ b/hydra
@@ -1 +1 @@
-Subproject commit 71784150d00655e8ebfb65026ea97e2d9dd6fb68
+Subproject commit 9d73ff39c0d2c43ab9799ea824698b4f7424c7b8