[hailtop.batch] Fix ServiceBackend close (#11337)
[hailtop.batch] Fix ServiceBackend close (#11337)

* [hailtop.batch] Fix ServiceBackend close

* fix
hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail,hail-is/hail