tox: Replace py344 with py34
tox: Replace py344 with py34

tox does not know what "py344" is and just runs the tests on your
default Python version instead.

For a complete list of default enviroments, see
https://tox.readthedocs.io/en/latest/example/basic.html#a-simple-tox-ini-default-environm

beerfactory/hbmqtt