I know the warning comes from txaio, but, in fact, this is autobahn-python that uses the old deprecated log calls.

(Will try to do some PR later)

edit: changing warn by warning breaks all twisted tests, Logger has no attribute warning ...

ORIG TITLE: "txaio/aio.py:202: DeprecationWarning: The 'warn' method is deprecated, use 'warning' instead"