Cadillac and “Entourage” creator Doug Ellin today debuted a short film that explains super-agent Ari Gold’s journey back to Hollywood after a short-lived retirement. Played by Jeremy Piven on the hit HBO series, Ari was last seen retiring to Italy in the show’s final episode. The upcoming Warner Bros. Pictures, Home Box Office and RatPac-Dune Entertainment film “Entourage,” in theaters June 3, brings the entire cast back together for the first time since the series finale.