add python 3 unit test jobs
add python 3 unit test jobs

Change-Id: Ie33552c5130acb89b31bb57ee13477ab101f9955
Signed-off-by: Doug Hellmann <0798ebecfb7bc4dfb9d0445c2fa030eb64e1fa1c@doughellmann.com>

openstack/training-labs,openstack/training-labs,openstack/training-labs