Merge "Update hacking for Python3"

ansible/library/kolla_toolbox.py

kolla_ansible/tests/unit/test_address_filters.py

kolla_ansible/tests/unit/test_filters.py

lower-constraints.txt

test-requirements.txt

tests/test_kolla_docker.py

tools/validate-all-file.py

tools/validate-yaml.py

tox.ini