Contemporary music is filled with great unreleased albums — the Beach Boys’ “Smile,” Marvin Gaye’s “Love Man,” the Clash’s “Rat Patrol From Fort Bragg,” David Bowie’s soundtrack to “The Man Who Fell to Earth,” multiple titles from Prince, Kanye West and Neil Young — many of which were never truly existed in anything resembling finished form. Usually, such albums turn out to be overblown in terms of their significance, leaving die-hard fans tryin…