virt: migration: rename helper function

rename helper function to be a bit more consistent
with the new style guidelines.

Change-Id: Ida7287528456763d641bc465dfd6e5e8e83f3f62
Signed-off-by: Francesco Romani <fromani@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28355
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-by: Vinzenz Feenstra <vfeenstr@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>