A federal judge cleared the way for a former Cook County sheriff’s officer to challenge his firing for a second time.In a written opinion last week, U.S. District Judge John Z. Lee vacated the decision by the Cook County Sheriff’s Merit Commission to terminate Robert Bless’ employment.Lee held the May 2013 decision is void as a matter of Illinois law because the merit board was unlawfully constituted at the time.Then-board member John R. Rosales was not lawfully appointed to serve in his position and …