WASHINGTON (Reuters) - Sarah Palin is shrugging off a controversial new HBO movie on Friday that portrays her as unstable and unprepared for the 2008 vice presidential run that made her a Republican political star. The television premiere of "Game Change" is on Saturday, based on a book of the same name by journalists John Heilemann and Mark Halperin about Republican John McCain's 2008 presidential campaign. Both Palin, who is portrayed by Julianne Moore in the movie, and McCain have said they will not watch the movie. ...