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/tnc/tnccs-20-ev-pt-tls/pretest.dat

@@ -14,7 +14,7 @@ alice::/usr/local/bin/init_tnc
 alice::rm /etc/swanctl/x509/aliceCert.pem
 alice::rm /etc/swanctl/rsa/aliceKey.pem
 alice::systemctl start apache2
-alice::systemctl start strongswan-swanctl
+alice::systemctl start strongswan
 alice::swanctl --load-creds
 winnetou::ip route add 10.1.0.0/16 via 192.168.0.1
 dave::ip route add 10.1.0.0/16 via 192.168.0.1