This de Blasio administration official set one heckuva bad example for the teens she was hired to keep out of jail. Reagan Stevens, a deputy director in the Mayor’s Office of Criminal Justice, and two young men were arrested for illegal weapons possession while sitting in a double-parked car near the scene of a Saturday night shooting in Queens, cops said. A loaded, 9-mm. semiautomatic pistol with its serial number defaced was hidden in the car’s glove box, and there was a spent shell casing on the floor