fixed nightly test script
fixed nightly test script

added prefix to xtern configure so dync_hook built can succeed.  now all
17 testcases pass.

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