vdsm-upgrade: adds wrapper to ovirt-node-upgrade

Currently ovirt-node provides ovirt-node-upgrade tool which
should replace vdsm-upgrade. This patch re-write vdsm-upgrade
as wrapper of ovirt-node-upgrade for legacy systems.

Change-Id: I7b997d70a440545497246d1a19d9671b054a56a5
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1079087
Signed-off-by: Douglas Schilling Landgraf <dougsland@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/28244
Reviewed-by: Dan Kenigsberg <danken@redhat.com>