Tony Burton, the veteran character actor best known for his brief but memorable appearances as the no-nonsense trainer and corner man in the first six “Rocky” movies, has died. He was 78. Burton’s wife, Aurelian, says the actor died of pneumonia Thursday at a Southern California hospital. Failing health had prevented him from appearing in “Creed,” the seventh “Rocky” movie. Sylvester Stallone is nominated for an Oscar for that film in this year’s Academy Awards, which will be presented Sunday.