[dt-test] automated tests failed

[DITrack Testbot]

=== trunk, r1643 by gli: FAIL (1 tests failed)
 * test failed: lock/low_level_lock.tc (tail of the error log follows)
    Traceback (most recent call last):
      File "./test.py", line 108, in ?
        (child_pid, child_pipe) = new_child("w", sleep_after_signal=4)
      File "./test.py", line 54, in new_child
        lock = DITrack.Util.Locking.lock(open(lockfile, "w"), mode)
      File "/X/testbox/ditrack/trunk.r1643/DITrack/Util/Locking.py", line 89, in lock
        raise DITrack.DB.Exceptions.DBIsLockedError
    DITrack.DB.Exceptions.DBIsLockedError