- mmap_seized returns only NULL on error, drop
   redumdant test
 - setup control block in one group
 - no need for err_free label, xfree handles NULL easily
 - prepare registers for munmap_seized call on error path
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Pavel Emelyanov <xemul@parallels.com>