Andy Cohen is coming clean about some of the more contentious behind-the-scenes "Housewives" exits, including one couple who "went for blood" after they were let go from "The Real Housewives of New York."In the new book "Not All Diamonds and Rosé: The Inside Story of the Real Housewives from the People Who Lived It," the Bravo scion said Alex McCord and her husband, Simon van Kempen, took their firing so hard that they essentially tried to undermine the show."[They] went for blood after we