A sergeant at the Cook County Jail who was denied a promotion because his disabilities limit his ability to respond to violent situations does not have a case for disability discrimination, a federal judge held.In a written opinion Tuesday, U.S. District Judge John F. Kness granted summary judgment in favor of Sheriff Thomas J. Dart and three jail administrators named as defendants in a lawsuit Larry Tate filed under the Americans with Disabilities Act.The suit alleged the defendants ran afoul of the ADA by failing to …