Bring your dog with you to the board meeting lol, let them see how "vicious" he is with his wagging tail and kisses. I'd say if it's not in your contract and you really want to keep him get liability insurance on him, you can get it through a pet insurance company or through your regular home insurance. Get his "mental" health tested by a vet if there's some way of doing so, and get a written paper from them saying your dog is sound/safe tempered. Then you have proof of insurance and can go to court with it and most likely win. Worst case scenario somehow they say "YOU MUST MUZZLE!" then train him to wear a muzzle. I mean how often are you hanging outside your condo with the dog besides going potty? I don't know too many condos that have a yard for hanging out in... maybe you do though? Otherwise....move and get a house if it's in your means.
Your best bet to take to fight to them...You need to educate the board with facts as well as show them how friendly pits are..I know this can be done...My neighbors knock on my door and ask if my dog can come out to play with theirs because they like my dog teaching theirs good habits...Get hold of your local pit club and ask some of the more gentile pits to come over and talk with your board...Its hard for people to be scared of dogs when they are petting them...