Rafer Johnson, the breathtaking Olympic gold medal winner who became an adored symbol of good sportsmanship and civic generosity, died Wednesday at his home in Sherman Oaks. He was 86. The Olympian’s death was confirmed by his family. Johnson’s legacy was interwoven with Los Angeles’ history, beginning with his performances as a world-class athlete at UCLA, and punctuated by the night in 1968 when he helped disarm Robert F. Kennedy’s assassin at the Ambassador Hotel. The son of Texas farmworkers who moved to California when he was young, Johnson rose to become the World’s Greatest Athlete, the unofficial title bestowed...