Currently all values of constants should be continuous,
because cr_fdset_open is used for opening images for all namespaces.

The next patches will rework this code and image files will be opened
per namespace, then all these ugly settings of one constant to another
will be removed.
Signed-off-by: Andrey Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>