core: support the newly-tagged vdsm-4.13

vdsm-4.13 would be part of oVirt-3.3.1.

Change-Id: I12dacd46973cde693105c21ae5bc41aec7fe7863
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Signed-off-by: Yair Zaslavsky <yzaslavs@redhat.com>