THE DEVIL’S REJECTS **½ (Comcast Movies: Free Movies) The second film to be directed by the heavy-metal rocker Rob Zombie is actually a pretty good, if almost completely scurrilous, homage to the cheap drive-in revenge films of the 1970s. Fans of the genre will be in B-movie heaven picking off the cameo appearances, but the main plot, about a kill-crazed clan of psychos, wallows too heavily in sadism. Fans would say that’s the point - so let ’em. (PG; runs through Sept. 20) TY BURR