Add comment in update_source.
Add comment in update_source.

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