Fixed automatic port allocation in bind_sockets.

bind_sockets should use the same port on IPv4 and IPv6 if port=None.
Merge pull request #977 from schlamar/fix-port-allocation

Fixed automatic port allocation in bind_sockets.
Disable port-allocation test on mac to avoid annoying firewall prompts.
Add a warning label to WSGIContainer.
Fix bit-rotted app engine tests.

sys.argv is no longer empty in dev_appserver.