In Barry Levinson’s latest change-of-pace comedy, two Belfast barbers — one Protestant, one Catholic — try to make it big as toupee salesmen. Of course, they’re woefully inept, bumping up against both the IRA and the Brits, as well as wig-snatching dogs, defecating cows, and a possible serial killer. Meanwhile, the movie listlessly meanders from deadpan whimsy to clodhopping farce to more serious social comment. The eclectic Levinson (Diner, Rain Man, Wag the Dog) is clearly a man of many cinematic moods. This time, however, they’ve left him in a muddle.