VALHALLA, N.Y. — It was quiet beneath the mountain laurel shrubs shielding the grave of the composer Sergei Rachmaninoff from the late-summer sun. The furor is 4,500 miles away, in Russia, its indelible voice in every melodic line he wrote — a different Russia, a different sensibility, a different life, different time. Resolutely nationalistic Russians want his body back. His great-great-granddaughter, Susan Sophia Rachmaninoff Volkonskaya Wanamaker, says “nyet.” Or she might, if she spoke Russian, but probably not. In a conversation about where his remains belong, she repeatedly used words like “dignity” and “respect.”