LOS ANGELES (Reuters) – Dale Robertson, the star of scores of Hollywood Westerns in the 1950s and 1960s, has died at the age of 89 in Southern California, Scripps Memorial Hospital in La Jolla said on Thursday. Robertson, who was best known for his role of special agent Jim Hardie in the NBC television series “Tales of Wells Fargo” from 1957-1962, died on Tuesday, the hospital said. The “Sitting Bull” star had been in poor health for about two years and had a cancer diagnosis last week, his niece, Nancy Love Robertson, told The Oklahoman newspaper. …