add the py2 version for python-docker and python-docker-pycreds packages.
add python-six and python-backport_ssl (for ph2 only) as python-docker dependencies.
verify the connection to docker engine at run time -
>>> import docker
>>> client = docker.from_env()
>>> client.images.list()
[<Image: 'hello-world:latest'>]
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
