testing: Converterd tnc to systemd

testing/tests/tnc/tnccs-20/posttest.dat

@@ -1,6 +1,6 @@
-carol::service charon stop
-dave::service charon stop
-moon::service charon stop
+carol::systemctl stop strongswan-swanctl
+dave::systemctl stop strongswan-swanctl
+moon::systemctl stop strongswan-swanctl
 moon::iptables-restore < /etc/iptables.flush
 carol::iptables-restore < /etc/iptables.flush
 dave::iptables-restore < /etc/iptables.flush