The Dodgers' magic number for clinching the NL West is down to zero — finally. After a season-worst five-game losing streak, they came through with one game left in the regular season and beat the stubborn Colorado Rockies 5-0 on Saturday night with a five-run seventh triggered by an RBI single from pinch-hitters Ronnie Belliard and an RBI double by Mark Loretta and six scoreless innings by…