minios: blkfront should set protocol node
minios: blkfront should set protocol node

From: Gerd Hoffmann <cad73e70082427fddc9be3baaf34e698dffd21c0@redhat.com>
Signed-off-by: Keir Fraser <630387d5cc1583f72f6a83b108d2df9830b77eef@citrix.com>

rowhit/xen-minios,rowhit/xen-minios,rowhit/xen-minios