FRANK CALLARI, the svengali behind the careers of Ryan Adams, The Mavericks and Lucinda Williams, has died. He was 55. The former hotel manager and self-employed club DJ, who passed away from natural causes, began his career as a music boss when he agreed to manage The Mavericks in the late 1980s. Moving to Nashville, Tennessee, Callari co-founded Lost Highway records in 2001, and signed Williams, Adams and Shelby Lynne, among others.