mnt: Don't treat ns roots as special when restoring

Namespace roots might be slave ones from another
namespace roots, so we should not treat them as
"always ready" for mounting but rely on general
logic in can_mount_now which tests slaves relations.
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

mount.c

@@ -2121,8 +2121,6 @@ static bool can_mount_now(struct mount_info *mi)
 	/* The root mount */
 	if (!mi->parent)
 		return true;
-	if (mi->is_ns_root)
-		return true;
 
 	if (mi->external)
 		return true;