More robust oldsys-preseed uploaded

To follow-up on my recent posting about oldsys-preseed: I uploaded a new version of netcfg yesterday that can be told via preseeding not to use a gateway. I also uploaded a new version of oldsys-preseed that will properly handle static IP configs without a netmask or gateway. Additionally, oldsys-preseed will now use DHCP when the static IP config is incomplete (i.e. when either the IP address or DNS are missing). This makes oldsys-preseed much more robust and will hopefully get rid of many problems users ran into with etch.