There was tension in Aba, Abia state, on Tuesday, July 7, after a policeman shot and killed an Abia revenue taskforce official and wounded another.    According to eyewitness reports, a policeman attached to Crunches, a fast-food restaurant, opened fire on members of Abia State Taskforce Board of Internal Revenue.   A member of the taskforce identified as Ifeanyi Kalu was killed instantly while another person was seriously injured, causing others to run for safety.   An eyewitness said trouble started when a driver of the fast-food …