Configure PPTP client of ddwrt

Add start-up command as following:

#!/bin/sh
sleep 120
PPTPSERVER=$(/usr/sbin/nvram get pptpd_client_srvip)
PPTPGWY=$(/usr/sbin/nvram get wan_gateway)
/sbin/route add -host $PPTPSERVER gw $PPTPGWY dev vlan2
/sbin/route del default
/sbin/route add default gw $PPTPGWY metric 100
/sbin/route add default dev ppp0
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE