A few years ago, Clayton and Joshua Britt we’re looking to form a band — nothing too unusual there. But the brothers ended up literally stopping Zach Bevill on the street and asked him to join what would become The Farewell Drifters. The group plays what’s described as harmonic roots music. In his conversation with WBHM’s Michael Krall, Bevill talks about the group’s sound and takes us back to that first encounter…