pep8 for commit, invalid, psa, rmi, and tag tets

Signed-off-by: James Molet <jmolet@redhat.com>

run_pylint.sh clean for: 

 subtests/docker_cli/commit/check_default_cmd.py
 subtests/docker_cli/invalid/invalid.py
 subtests/docker_cli/psa/psa.py
 subtests/docker_cli/rmi/delete_wrong_name.py
 subtests/docker_cli/tag/tag.py