minor: remove commented tern_exit prototype since no need to hook exit()
minor: remove commented tern_exit prototype since no need to hook exit()

hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,columbia/xtern,columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern