systemctl: honor "--no-legend" in 'list-sockets'
service: kill processes with SIGKILL on watchdog failure

Just calling service_enter_dead() does not kill any processes.
As a result, the old process may still be running when the new one is
started.

After a watchdog failure the service is in an undefined state.
Using the normal shutdown mechanism makes no sense. Instead all processes
are just killed and the service can try to restart.
systemctl: make systemctl is-enabled work for templated units

Patch resolves the problem that 'systemctl is-enabled' does
not work for templated units.

Without this patch, systemctl is-enabled something@abc.service
returned "No such file or directory", because it first checked
if /usr/lib/systemd/system/something@abc.service, etc. exists.
If systemctl is-enabled is called for templated units, this
check should be omitted and it should search for symlinks in
the .wants dirs right away.

This patch fixes the broken behaviour and resolves
  https://bugs.freedesktop.org/show_bug.cgi?id=55318.

[zj: fixed the patch to still check for broken symlinks and
     masked instances. Also removed untrue assumptions from
     the patch description.]
man: Document missing options