Drop minversion (tox.ini) for centos7
Drop minversion (tox.ini) for centos7

Change-Id: I8827a609bdc4f54e40630b7145d71fcb2d023a1a
Signed-off-by: Paul Belanger <e7139c8e6c4ea75cc1c287ce081b2dc0f3ab39ec@redhat.com>

openstack/ansible-role-nodepool,openstack/ansible-role-nodepool