fixed minor 64-bit bug in unittest/random.h
fixed minor 64-bit bug in unittest/random.h

levendlee/thrust,bfurtaw/thrust,hemmingway/thrust,Vishwa07/thrust,malenie/thrust,rdmenezes/thrust,google-code-export/thrust,google-code-export/thrust,julianromera/thrust,levendlee/thrust,h1arshad/thrust,levendlee/thrust,hemmingway/thrust,levendlee/thrust,malenie/thrust,hemmingway/thrust,google-code-export/thrust,google-code-export/thrust,bfurtaw/thrust,bfurtaw/thrust,UIKit0/thrust,hemmingway/thrust,allendaicool/thrust,bfurtaw/thrust,UIKit0/thrust,malenie/thrust,lishi0927/thrust,rdmenezes/thrust,Vishwa07/thrust,allendaicool/thrust,allendaicool/thrust,lishi0927/thrust,h1arshad/thrust,rdmenezes/thrust,julianromera/thrust,malenie/thrust,julianromera/thrust,allendaicool/thrust,rdmenezes/thrust,lishi0927/thrust,lishi0927/thrust,h1arshad/thrust,julianromera/thrust,UIKit0/thrust,Vishwa07/thrust,h1arshad/thrust,Vishwa07/thrust,UIKit0/thrust