Fix martian handling for IPv4.
Fix martian handling for IPv4.

jech/babeld,wlanslovenija/babeld,dtaht/babeld-shortrtt-metrics,Gwendocg/babeldToS,boutier/babeld,sudomesh/babeld,wlanslovenija/babeld,jech/babeld,Gwendocg/babeldToS,tcatm/babeld,woniullb/babeld,Drooids/babeld