files: drop O_TMPFILE from file descriptor flags

Unnamed temporary files are restored as ghost files.

If O_TMPFILE is set for the open() syscall, the pathname argument
specifies a directory, but criu gives a path to a ghost file.

(00.107450)     36: Error (criu/files-reg.c:1757): Can't open file tmp/#42274874 on restore: Not a directory
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/files-reg.c

@@ -1713,6 +1713,9 @@ int do_open_reg_noseek_flags(int ns_root_fd, struct reg_file_info *rfi, void *ar
 	u32 flags = *(u32 *)arg;
 	int fd;
 
+	/* unnamed temporary files are restored as ghost files */
+	flags &= ~O_TMPFILE;
+
 	fd = openat(ns_root_fd, rfi->path, flags);
 	if (fd < 0) {
 		pr_perror("Can't open file %s on restore", rfi->path);