By Tom Miles GENEVA (Reuters) - Talks between Russia and the United States may produce a chance of peace in Syria, Kofi Annan, the former U.N. secretary-general who tried unsuccessfully to forge a deal to end the war in 2012, said on Tuesday. "In this situation the role of Russia and the U.S. are key. "No war goes on forever," Annan told a packed audience of students and diplomats, including Lakhdar Brahimi, who succeeded him as the Syria mediator, but also quit after failing to forge agreement between the warring sides.