Log xml in libvirt _create_domain failures

When an error occurs defining, launching or enabling hairpin mode on a
libvirt domain, log the xml for reproduction and analysis.

Fixes bug 1183534

Change-Id: Ic8f1d11c5a92779c686b7248895bbc6f2cfdbf0b
Merge "Log xml in libvirt _create_domain failures"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp