Actor and playwright Sam Shepard is the latest in the ever-extending line of theater types who would like a piece of President Bush, and he’d like it before November 2, if possible. That’s awfully short notice in the New York theatre world, but Shepard’s new play found a willing short-order team at Manhattan’s New School University. Performances of The God of Hell, which Shepard describes as “a takeoff on Republican fascism, in a way,” begin four days before the presidential election.