restore: Call prepare_fds() in restore_one_zombie()

Zombie may be choosen as parent for task helper
during solving pgid dependences. In this situation,
it becomes to share fdt with the helper and it has
to call prepare_fds() to decrement fdt->nr.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/cr-restore.c

@@ -963,6 +963,9 @@ static int restore_one_zombie(CoreEntry *core)
 
 	pr_info("Restoring zombie with %d code\n", exit_code);
 
+	if (prepare_fds(current))
+		return -1;
+
 	if (inherit_fd_fini() < 0)
 		return -1;