undercloud: do not hardcode eth1 for public interface
undercloud: do not hardcode eth1 for public interface

Instead, rely on local_interface parameter from undercloud.conf like it
was with instack-undercloud.

Depends-On: I94de786a4e2d6bfbc66e08f32ea65c217ea35268
Change-Id: Id46256b66aa43c38a6a6501d2f26dfb85009b1ef

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