An off-duty police officer ended up on the wrong side of the law Friday night, shooting a man who had purposely knocked over the cop's beer in a lower Manhattan bar, police said Saturday. The injured 23-year-old, whose name was not released, was taken to St. Vincent's Hospital Manhattan in stable condition, police said. Bernard Marti, who is assigned to Harlem's 25th Precinct, was drinking in Cordato's Deli and Bar at 94 1/2 Greenwich St. at 10:30 p.m. Friday when a man knocked over Marti's beer, police sources said. That man voluntarily bought Marti a new beer but intentionally knocked...