Fix another instance of missed use of neigh->id[0].
Fix another instance of missed use of neigh->id[0].

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