setupopenvpn - changes to ensure link will re-establish on reboot

Chicken and egg situation with nat iptables rules resolved so that
the rules are only applied if the tunnel is up.
setupopenvpn DMZ tunnel creation bug fix after second test.

setupopenvpn now successfully creates vpn tunnel with nat rules.
After a server restart cron runs the openvpnclients script on the pdc which
checks for any servers that need the tunnel restarting.