In a food processor, combine the flour, cornmeal, salt and chives and process to blend. Add the butter and pulse a few times until the pieces are the size of small peas. Add the shortening and pulse a few times. Sprinkle the ice water over the mixture and pulse until the dough barely comes together. Scrape the dough onto a lightly floured work surface and knead to form a ball. Flatten the ball into a disk, wrap in plastic and refrigerate for 1 hour, or until firm.