CBS canceled “Viva Laughlin” as everyone expected. The only surprise is that the network let it air twice. The Las Vegas “murder-mystery with music” bombed in its post-“CSI” debut, then continued its crash in its regular Sunday night slot. “Viva Laughlin” was dead on arrival, savaged by the critics. “If Elvis isn’t already dead, ‘Viva Laughlin’ just might kill him,” Robert Bianco of “USA Today” wrote. CBS was hoping to mimic the BBC hit “Viva Blackpool,” but its execution was ridiculously, laughingly bad. Music is an integral part of many TV shows, but “Viva Laughlin”, seemingly afraid to be compared to “Cop Rock,” ABC’s noble failure, failed to embrace its song-and-dance. The lame writing and lousy acting didn’t help. Give CBS credit for trying something different. Better luck next time.