Busybox udhcpc dropped support for the -c option, instead it can be emulated by using -x 0x3d:id,
change the dhcp protocol script accordingly and filter all colons from the id while we're at it.
This change supersedes http://patchwork.openwrt.org/patch/1810/
git-svn-id: svn://svn.openwrt.org/openwrt/trunk@32573
3c298f89-4303-0410-b956-
a3cf2f4a3e73
-f -t 0 -i "$iface" \
${ipaddr:+-r $ipaddr} \
${hostname:+-H $hostname} \
- ${clientid:+-c $clientid} \
+ ${clientid:+-x 0x3d:${clientid//:/}} \
${vendorid:+-V $vendorid} \
$broadcast $dhcpopts
}