LOS ANGELES (Reuters) - The movie cast of "The Sound of Music" are reuniting for the first time in 45 years, with Julie Andrews and Christopher Plummer joining their seven fictional children in an October appearance on Oprah Winfrey's TV talk show, producers said on Monday. Andrews, Plummer, Charmian Carr (Liesl), and the actors who played the six other von Trapp family children will talk about making the 1965 Oscar-winning movie and their lives since it went on to become one of the most popular movie musicals ever. The reunion will be broadcast on October 29 on "The Oprah Winfrey...