closes #3045, #3123 for tornado < version 3.0

This fixes the ``gaierror: [Errno -9] Address family for hostname not supported`` error from  unassociated interfaces.

related to facebook/tornado#593 - but the fix was only applied to 3.0

I've verified that this fix works for tornado 2.1, 2.4, 2.4.1, and the behavior it fixes does not trigger on tornado 3.0

This was really annoying when I happend to get lose a wireless signal, or unplug from the network, and since it is only fixed in a version of Tornado that was release less than 2 weeks ago, I'd prefer it if we had a workaround in our code (though I understand that opinions may differ).