Swift service doesn't support IPv6

[Xiang Hui]

OS: ubuntu
Version: icehouse

Swift can't listen on the ipv6 address if it is setup on a separate node and report below error:

Traceback (most recent call last):
  File "/usr/bin/swift-proxy-server", line 23, in <module>
    sys.exit(run_wsgi(conf_file, 'proxy-server', default_port=8080, **options))
  File "/usr/lib/python2.7/dist-packages/swift/common/wsgi.py", line 381, in run_wsgi
    sock = get_socket(conf, default_port=kwargs.get('default_port', 8080))
  File "/usr/lib/python2.7/dist-packages/swift/common/wsgi.py", line 161, in get_socket
    family=address_family)
  File "/usr/lib/python2.7/dist-packages/eventlet/convenience.py", line 38, in listen
    sock.bind(addr)
  File "/usr/lib/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
socket.gaierror: [Errno -9] Address family for hostname not supported

This could be fixed as the way nova does https://bugs.launchpad.net/nova/+bug/1164822.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/116618

[OpenStack Infra (hudson-openstack)]

Change abandoned by Samuel Merritt (<email address hidden>) on branch: master
Review: https://review.openstack.org/116618
Reason: thanks to the eventlet maintainers for fixing this one!