After a California inmate beat two convicted child molesters to death with a walking cane, he decided to speak out about what went down behind bars. His words should serve as a warning. California State Prison at Corcoran (Photo Credit: Screenshot) Jonathan Watson, a 41-year-old California inmate, attacked David Bobb, 48, and Graham De Luis-Conti, 62, at the California Substance Abuse Treatment Facility and State Prison in Corcoran, NBC Los Ange…