shutdown: during final killing spree also send SIGHUP in addition to SIGTERM to deal with shells

This makes shutdown a bit faster if debug-shell.service is enabled.
swap: always track the current real device node of all swap devices, even when not active

This way, we can avoid executing two /bin/swapon jobs to be dispatched
for the same swap device if it is configured for two different paths.

Previously we were just tracking the device nodes of active swap
devices, which would not allow us to recognize the identity of two swap
devices before they are active.

https://bugs.freedesktop.org/show_bug.cgi?id=69835
core: include following set data in dump