You know you’re in trouble when Tom Brokaw is out for your blood. NBC’s most revered journalist is furious that Brian Williams is still in the anchor chair after he sheepishly admitted he hadn’t traveled on a helicopter hit by enemy fire. “Brokaw wants Williams’ head on a platter,” an NBC source said. “He is making a lot of noise at NBC that a lesser journalist or producer would have been immediately fired or suspended for a false report.” On Wednesday, Williams, 55, acknowledged that he had repeatedly said he was aboard a chopper that had been hit by a...