Enhance wsgi to listen on ipv6 address

* Check if the hostname is ipv6 and set the family appropriately
* Add test case for wsgi.Server and service.WSGIService

Change-Id: I6edd467467fa3d623d62e146750b3a6c42d8833c
Regenerate nova.conf.sample

Some pretty monstrous hacking in the extraction tool is required to
guess the group which options are in. It was pretty hacky to begin with
though.

Change-Id: Ie93dcfc82ab19af4e3cb7090bbb03d9efee83aa2
Merge "Enhance wsgi to listen on ipv6 address"
Merge "Regenerate nova.conf.sample"