preload-index.c: use the right index instead of the_index

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

preload-index.c

@@ -58,7 +58,7 @@ static void *preload_thread(void *_data)
 			continue;
 		if (ce->ce_flags & CE_FSMONITOR_VALID)
 			continue;
-		if (!ce_path_match(&the_index, ce, &p->pathspec, NULL))
+		if (!ce_path_match(index, ce, &p->pathspec, NULL))
 			continue;
 		if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
 			continue;