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-xfrmi/pretest.dat

@@ -7,8 +7,8 @@ moon::ip link set xfrm-moon-in up
 moon::ip route add 10.2.0.0/16 dev xfrm-moon-out
 moon::iptables -A FORWARD -o xfrm-moon-out -j ACCEPT
 moon::iptables -A FORWARD -i xfrm-moon-in -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