closes #3045, #3123 for tornado < version 3.0

related to facebook/tornado#593

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
addressing @minrk's PR feedback

* check tornado version
* log.warn about the monkeypatching
Merge pull request #3148 from ivanov/tornado-AI_ADDRCONFIG-patch

fix `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

closes #3045