At 88, filmmaker Ridley Scott has lived long enough to know that even extravagant praise deserves a little skepticism. So when informed that Quentin Tarantino had named his 2001 war epic “Black Hawk Down” the greatest film of the 21st century, Scott did not feign humility, accept the compliment, or launch into a defense of his own achievement. In fact, he wondered what Tarantino had ingested. “I wonder what he was on, because whatever it is, I w…