(Reuters) - Russia will not renew a decades-old agreement with Washington on dismantling nuclear and chemical weapons when it expires next year, Deputy Foreign Minister Sergei Ryabkov was quoted as saying on Wednesday. The death of the 1991 agreement, which had been renewed twice, is the latest in a series of hitches in relations between the United States and Russia and casts doubt on the future of the much-vaunted "reset" in relations between the Cold War-era foes. "The basis of the program is an agreement of 1991 which, by virtue of the time when it was conceived, the way it...