There’s nothing funny about the legal fight going on between the producers of “Dumb and Dumber” and the producers of the just-announced sequel. Last week, Red Granite Pictures, which is about to start production on “Dumb and Dumber To,” filed suit in LA to keep Brad Krevoy and Steve Stabler, producers of the Farrelly brothers’ original 1994 goofball comedy, away from the sequel. Now, according to Deadline.com, Krevoy and Stabler have filed a countersuit against Red Granite principals Joey McFarland and Riza Aziz, claiming their “unlawful and unethical conduct . . . will cause Red Granite to crash and burn.” It’s not clear what, if any, effect the wrangling will have on the new movie, which is set to start shooting with Jim Carrey and Jeff Daniels in the fall.