John R. Countryman, who was featured in a number of Hollywood films alongside stars like Shirley Temple and Barbara Stanwyck in the 1930s and 1940s while using the stage name Johnny Russell, has died. He was 91. Countryman, following his time in the movie business, served as an American diplomat for years and was appointed the U.S. Ambassador to Oman by President Ronald Reagan, a post he served in from 1981 to 1985. His daughter, Vanessa…