Johnny Depp is gone, but behold Kevin Bacon. The actor is in Boston shooting scenes for the Whitey Bulger movie. Bacon, who spent some time in the Hub while making “Mystic River,” is playing an FBI agent who supervised corrupt agent John Connolly. The movie, based on the book “Black Mass,” has a few more days of filming before director Scott Cooper and the crew leave town. Depp, who plays the notorious South Boston crime boss, filmed his final scene in Lynn earlier this week.