fix other usages of computation.stop
fix other usages of computation.stop

TurkServer/turkserver-meteor,HarvardEconCS/turkserver-meteor,TurkServer/turkserver-meteor,VirtualLab/turkserver-meteor,HarvardEconCS/turkserver-meteor,VirtualLab/turkserver-meteor,VirtualLab/turkserver-meteor,TurkServer/turkserver-meteor,HarvardEconCS/turkserver-meteor