prevent CloudStack from removing the VPN connection

If connecting the VPN takes some time, for example because
the other end is not (yet) up, CloudStack will delete
the VPN because the ipsectunnel.sh does not return in time.
The VPN connection then enters the Error state.

This change makes sure ipsectunnel.sh returns in time,
and lets ipsec connect in the background. If it all fails,
the connection enters Disconnected.

systemvm/patches/debian/config/opt/cloud/bin/ipsectunnel.sh

@@ -173,7 +173,7 @@ ipsec_tunnel_add() {
 
   if [ $passive -eq 0 ]
   then
-      sudo ipsec auto --up vpn-$rightpeer
+      sudo ipsec auto --up vpn-$rightpeer &
   fi
   if [ $checkup -eq 1 ]
   then