From DCist Contributor Oscar Bunoan It’s often said that bad luck comes in threes. In Vietnam, for example, a photo of three people represents bad luck. However, Vietnam is a restless, 22-hour flight away and Greg Cahill (owner of the successful Whitlow’s on Wilson) and Jonathan Williams (Whitlow’s general manager) are not superstitious men who rest their beliefs in ancient folklore. No self-respecting restaurateur, especially these two locally respected entrepreneurs, would conceive their restaurant on…