instack-virt-setup can't use dnsmasq lease file anymore

[Thomas Herve]

I tried to use instack-virst-setup with a recent libvirt (1.2.17) and I got the following error:

instack never got an IP address from the libvirt default network.
cat: /var/lib/libvirt/dnsmasq/default.leases: No such file or directory

As it turns out, libvirt doesn't specify the lease file option in dnsmasq anymore (since 1.2.11).

It should be easy to retrieve it in a different way though.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/232584

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/232584
Committed: https://git.openstack.org/cgit/openstack/instack-undercloud/commit/?id=75e7a7f8350d736d3c0957cec6eff234d7f7c8c0
Submitter: Jenkins
Branch: master

commit 75e7a7f8350d736d3c0957cec6eff234d7f7c8c0
Author: Thomas Herve <email address hidden>
Date: Thu Oct 8 17:02:58 2015 +0200

    Don't use dnsmasq lease file to retrieve address

    Since libvirt 1.2.11, libvirt doesn't ask for dnsmasq to fill a lease
    file, thus instack-virt-setup fails to retrieve it at the end of the
    installation. Simply using arp fixes that.

    Change-Id: Ie6757a7b0c224d89ebab992ef147b6fc04f774cc
    Closes-Bug: #1504179