Avoid microoptimisation in route_changed.
Avoid microoptimisation in route_changed.

This is brittle, and prevents me from making route selection smarter.

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