This patch fixes integration with systemd-journald, and also sets the
now mandatory KillMode.
When running on systems with systemd-journald certain considerations
must be taken. These are listed here:
https://www.freedesktop.org/wiki/Software/systemd/syslog/
In it simplest form, the system as a whole logs through journald and
a BSD syslog daemon then gets its log messages from journald.
NOTE: due to issues with the Debian packaging of rsyslog, the sysklogd
packages cannot be used to replace rsyslog. First rsyslog must
be purged to clear the syslog.socket symlink, then sysklogd can
be installed.
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>