Fix when using classful notation

There is antother case that failed, basically when the network ranges can be expressed without CIDR notation, quagga defaults to it, so I had to lookup for the netmasks and add them to the networks defined.

This is an example of what was failing:

    *>i223.255.230.0    149.6.123.123       165090    100      0 1254 7473 4761 45727 45127 i
    *>i223.255.231.0    149.6.123.123        21030    100      0 1254 6762 7713 45127 i