split restore-net-conf away of vdsmd.init service

There is no need to revert network configuration when vdsmd is
restarted, only when the host is rebooted after being fenced.

This becomes painfully visisble if vdsm is restarted due to spm
failover, and while at it - rolls back an unrelated network
configuration.

Change-Id: Iabe00320d090b9055c3d619260ed57ee953702f1
Signed-off-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/10334
Reviewed-by: Antoni Segura Puimedon <asegurap@redhat.com>
Tested-by: Meni Yakove <myakove@redhat.com>