The New Brunswick folk trio sets aside its banjos and ukuleles and plugs in for this stripped-down set of classic rock. “Laisse-le pas te laisser” and “Motel 1755” channel prime late-‘70s Fleetwood Mac and Bruce Springsteen, while “Still Pareille” might be the year’s most romantic prom ballad. Still, it’s the girl-group charms of “Johnny Boy” that will leave young couples dancing.