Fix bug in sample
Fix bug in sample

cybernet14/ecmascript-asyncawait,lukehoban/ecmascript-asyncawait,mrmayfield/ecmascript-asyncawait,knightf/ecmascript-asyncawait,modulexcite/ecmascript-asyncawait,timruffles/ecmascript-asyncawait,jasonhowmans/ecmascript-asyncawait,tc39/ecmascript-asyncawait,anba/ecmascript-asyncawait,barkinet/ecmascript-asyncawait,anba/ecmascript-asyncawait,cybernet14/ecmascript-asyncawait,lukehoban/ecmascript-asyncawait,modulexcite/ecmascript-asyncawait,pwz3n0/ecmascript-asyncawait,pducks32/ecmascript-asyncawait,tc39/ecmascript-asyncawait,pwz3n0/ecmascript-asyncawait,knightf/ecmascript-asyncawait