John Schlesinger decided not to attend the Academy Awards in 1970, even though his film “Midnight Cowboy” had been nominated for Best Picture and he was up for Best Director. On the evening of April 7, 1970, otherwise known as Oscar night, the British director remained in London with his American boyfriend, the photographer Michael Childers. Schlesinger didn’t want to make the brutal 24-hour roundtrip flight to Hollywood and back, and besides, he was well into production on his follow-up film, “Sunday Bloody Sunday.” For him, it was a very personal project, and, in some ways, an even more controversial film than “Midnight Cowboy.”