Will need it to handle vvar zones in a special way.

Because VMA_UNSUPP never goes into the image file
lets reuse bit 12 for VVAR.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@parallels.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>