Barbra Streisand made a political pit stop at the palatial pad of Sen. John Kerry the other night, shortly after the Demmie diva mocked President Bush from the stage at the TD Banknorth Garden. According to our Streisand spies, the Funny Girl and her hubby, James Brolin, pulled up to 19 Louisburg Square after midnight in a rather un-divalike minivan for a late-night supper and political gabfest with her fave Boston liberal and his daughter, Alexandra. Earlier in the evening, after belting out “Happy Days Are Here Again” during the soapbox portion of the show, Streisand told the throng “I...