VDSM now writes its version number in VDSM-generated ifcfg files

Change-Id: Ida8a540356e04d86eb19e05149861d800d8f7313
Signed-off-by: Assaf Muller <amuller@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/17566
Reviewed-by: Dan Kenigsberg <danken@redhat.com>