fixed typo in dync_hook/Makefile
fixed typo in dync_hook/Makefile

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