Turns out Ol’ Roy signed off on Hubert Davis long ago as a Tar Heel
PHOTO: Roy Williams and Hubert Davis coaching from the sidelines. By TOM SHANAHAN All that was needed before Hubert Davis was officially introduced as North Carolina’s new basketball coach was to hear his predecessor had signed off on the promotion from assistant coach. Turns out Roy Williams had endorsed Davis as a Tar Heel long before the Monday announcement and the formal press conference on Tuesday at the Dean E. Smith Center. If he hadn’t, Davis' historic hiring…