Change kolla_config from required to optional in pep8.
Change kolla_config from required to optional in pep8.

We've decided to use volumes for configuration wherever possible.
This means moving away from kolla_config blocks in the templates.
Update pep8 to reflect this.

Change-Id: If1ec40d0e5a515eed35e0cd04711079294f358c3

dprince/tripleo-heat-templates,openstack/tripleo-heat-templates,dprince/tripleo-heat-templates,openstack/tripleo-heat-templates