Old Crow Medicine Show aren't revivalists. They're anachronists. On their fourth full-length, produced by Don Was, the Nashville quartet mash up a well-nigh 19th-century sound — hopped-up folk, bluegrass, country and gospel — with lyrics that are firmly planted in the 21st century. "Huff paint, cocaine, playing chicken with a train/Smack dab, meth lab, mellow out, rehab," hoots Ketch...