Fixes <https://issues.guix.gnu.org/54812>.
Starting with Shepherd 0.9.0 and the use of 'make-inetd-constructor' in
commit 808b9e850491c7b1d867a5f1f4d5ee6f61f345d4, systems might be
running transient Shepherd services such as those corresponding to SSH
connections. Before this change, 'shepherd-service-upgrade' would have
those transient services in the list of services to unload; concretely,
that would lead all SSH connections to be closed upon 'guix system
reconfigure'.
* gnu/services/shepherd.scm (shepherd-service-upgrade): Remove transient
services to TO-UNLOAD.
eeb8ac43c8