We are trying to get a working 64bit qemu cpu model in the gate for nova
live migration testing. It appears that we need to make this change
prior to nova starting.
Make the change in configure_libvirt() to handle this along with the
other libvirt config updates. This allows us to restart the libvirt
service once. This function calls a python tool which parses and updates
the XML if necessary.
Change-Id: I00667713bfba67ab8cedbcb1660ff94d4f4bcc07
edd6048168