  o Minor bugfix (unit tests):
    - Make unit tests pass on IPv6-only systems, and systems without
      localhost addresses (like some FreeBSD jails).
      Fixes bug #17632; bugfix on unit tests in 0.2.7.3-rc.
      c464a367728d was a partial fix for this issue in #17255;
      it was released in unit tests in 0.2.7.4-rc.
      Patch by "teor".
