LOS ANGELES — A homeless man was arrested and charged with arson for starting a tiny blaze in August near the spot where a gigantic wildfire erupted several days later, killing two firefighters, homicide detectives said Monday. Babatunsin Olukunle, 25, is the strongest lead to date in the arson investigation stemming from a fire that destroyed 89 homes, burned 250 square miles of national forest and killed two firefighters when their truck plunged off a road. It was one of the largest fires in Southern California history.