One suspects the dinner table conversation about making “ Family Movie ” had to go a bit better for Kevin Bacon than for Jack Smith, the B-movie director he plays in this horror movie send-up. But the fear that Bacon has gathered everyone for something indulgent is quickly disabused in the silly and gory comedy where the fun all are having on screen extends to those who aren’t directly related. Like the scrappy productions that Jack specializes in, “Family Movie” is crude in most respects,