Bill Clinton partied with rock stars including Bruce Springsteen, Paul McCartney, Jon Bon Jovi, John Mellencamp and Pink Floyd’s Roger Waters in the Hamptons Friday night while wife Hillary Clinton sat home baby-sitting their granddaughter. Spies told Page Six that Clinton was the first guest at an after-party hosted by Jimmy Buffett at the Blue Parrot in East Hampton for the Bill Murray–Bruce Willis movie “Rock the Kasbah.” “Clinton . . . held court at the bar,” said a spy. “He said he’d had to pick up Hillary coming back from a three-day campaign trip