Comment 2 for bug 1277494

Seen this again here: http://logs.openstack.org/02/68402/2/gate/gate-tempest-dsvm-full/b4850b1/logs/

e.g.

 $> grep '\(Start\|End\) to_xml' screen-n-cpu.txt.gz | sed 's/\(.*libvirt.driver\) .* \(\(Start\|End\) .*\)/\1 \2/' | cut -c 1-70 | tail -5
 2014-02-10 10:30:18.457 DEBUG nova.virt.libvirt.driver Start to_xml ne
 2014-02-10 10:30:18.695 DEBUG nova.virt.libvirt.driver End to_xml xml=
 2014-02-10 10:30:31.587 DEBUG nova.virt.libvirt.driver Start to_xml ne
 2014-02-10 10:30:31.797 DEBUG nova.virt.libvirt.driver End to_xml xml=
 2014-02-10 10:30:47.212 DEBUG nova.virt.libvirt.driver Start to_xml ne