Remove duplicate PreConfig definition
Remove duplicate PreConfig definition

We had two exactly the same definitions of PreConfig in
docker_steps.j2.yaml. We should remove one of them.

I chose to remove the first definition, as the 2nd definition is amended
by change I674a4d9d2c77d1f6fbdb0996f6c9321848e32662, so we'll avoid a
conflict.

Change-Id: If65e30daefcf6552e085c7648c6691b7068834d4

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