o Minor features (testing):
    - Use the approx_time() function when setting the "Expires" header
      in directory replies, to make them more testable. Needed for
      ticket 30001.
  o Minor bug fixes (testing):
    - Check the time in the "Expires" header with approx_time().
      Fixes bug 30001; bugfix on 0.4.0.4-rc.