[downloader] Abort download immediately if buffer resizing fails

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/downloader.c

@@ -183,6 +183,8 @@ static int downloader_xfer_deliver ( struct downloader *downloader,
 
  done:
 	free_iob ( iobuf );
+	if ( rc != 0 )
+		downloader_finished ( downloader, rc );
 	return rc;
 }