A federal appeals court Thursday upheld the contempt conviction of an attorney who criticized prosecutors for failing to call a particular witness to the stand during his client’s fraud trial.The 7th U.S. Circuit Court of Appeals affirmed U.S. District Judge Ronald A. Guzman’s determination that Michael I. Leonard of LeonardMeyer LLP deliberately flouted an order to refrain from mentioning the “missing” witness in front of jurors.Leonard mentioned the witness during his closing argument in the trial …