Fix boolean short circuit problem when there are no broker offsets yet
Fix boolean short circuit problem when there are no broker offsets yet

WanliTian/Burrow,linkedin/Burrow,wikimedia/operations-debs-golang-burrow,evertrue/Burrow,socrata/Burrow,saleswise/Burrow,ContentSquare/Burrow,Connexity/Burrow,wikimedia/operations-debs-burrow,wikimedia/operations-debs-burrow,wilmer-daza/Burrow,spredfast/Burrow,ehorne/Burrow,matsu-chara/Burrow