tox -e pep8 faster - just minimal deps
tox -e pep8 faster - just minimal deps

for pep8 (via flake8) check,
there is no use for all deps/test-deps to install
for pep8 test (static file analysis)
neither it runs on 'infrared-installed-in-venv'

this makes just 'hacking' installed for pep8 testing,
(it pulls pep8 and flake8
(+few more OStack specific things like pyflakes, six, pbr...)

Change-Id: Idaf93f8e2435f1640363ea0325db7a51af0b9e20

redhat-openstack/infrared,okolisny/InfraRed,okolisny/InfraRed,redhat-openstack/infrared,redhat-openstack/infrared,okolisny/InfraRed