Fix computation of channels_size.
Fix computation of channels_size.

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