ntfsclone: fix restore from stdin

When doing a ntfclone-restore from stdin and stdin is then closed,
ntfsclone will loop forever:
$ cat corrupt_image.gz | gzip -d | ntfsclone -r -O somedisk -

With this patch the io_all() loop will return an error when the
input-stream is closed.

ntfsprogs/ntfsclone.c

@@ -529,6 +529,8 @@ static int io_all(void *fd, void *buf, int count, int do_write)
 		if (i < 0) {
 			if (errno != EAGAIN && errno != EINTR)
 				return -1;
+		} else if (i == 0 && !do_write && opt.restore_image) {
+			return -1;
 		} else {
 			count -= i;
 			buf = i + (char *) buf;