Updated openstack/openstack
Project: openstack/nova  8e73356c745e79007b8b13d6a9bb99b7d3ae3528

libvirt: add '_' prefix to all get_guest_*_config methods

The get_guest_*_config methods are all internal helpers so should
have a '_' prefix to indicate they are not part of public virt
driver API.

Related-bug: #1333219
Change-Id: I76108c4992144cc7c3273bfd753aa76f7a821a56