testing: Use renamed systemd unit

While the alias is available after enabling the unit, we don't
actually do that in our testing environment (adding a symlink manually
would work too, then again, why not just use the proper name?).

testing/tests/route-based/net2net-vti/posttest.dat

@@ -1,6 +1,6 @@
 moon::swanctl --terminate --ike gw-gw
-moon::systemctl stop strongswan-swanctl
-sun::systemctl stop strongswan-swanctl
+moon::systemctl stop strongswan
+sun::systemctl stop strongswan
 moon::iptables-restore < /etc/iptables.flush
 sun::iptables-restore < /etc/iptables.flush
 moon::ip tunnel del vti-moon

testing/tests/route-based/net2net-vti/pretest.dat

@@ -12,8 +12,8 @@ sun::ip link set vti-sun up
 sun::ip route add 10.1.0.0/16 dev vti-sun
 sun::iptables -A FORWARD -i vti-sun -j ACCEPT
 sun::iptables -A FORWARD -o vti-sun -j ACCEPT
-moon::systemctl start strongswan-swanctl
-sun::systemctl start strongswan-swanctl
+moon::systemctl start strongswan
+sun::systemctl start strongswan
 moon::expect-connection gw-gw
 sun::expect-connection gw-gw
 moon::swanctl --initiate --child net-net