Tough situation. I really believe the officer feared for his life, though I do wonder how much of that fear came from already being tense or on-edge. As Jason said, this case wouldn't be justified if it was a citizen who took the shots. I'm glad the guy is alive, and I'm glad the officer doesn't have to live with killing a man over the flash of a cane, and while I don't want to condemn him, I will say that I really am not sold on saying that a reasonable person would fear for their life in that situation. I dunno. It turned out about as well as it could, I guess.
Oh, and if they want to pass a law, pass one requiring better lighting on police cars. What the hell is a pamphlet going to do when someone really does have a shotgun and the officer assumes it's a cane? Jackasses...