Fix duplicate host resource

In some circumstances, the puppet-coe class may cause a duplicate
resource error due to host definition clashing with
puppet_openstack_builder's setup.pp manifest.  This patch prevents
the problem by creating the host entry with create_resource
instead of creating it explicitly.

Closes-Bug: #1292772
(cherry picked from commit 4ead041c3eba175ff21ec95595312024e3691a85)