Don't call neighbour_rxcost() in the middle of a message
Don't call neighbour_rxcost() in the middle of a message

neighbour_rxcost() calls update_neighbour which might send some messages,
so make sure we don't call it in the middle of the txcost message.

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