tmp-objdir: do not migrate files starting with '.'

This avoids "." and "..", as we already do, but also leaves
room for index-pack to store extra data in the quarantine
area (e.g., for passing back any analysis to be read by the
pre-receive hook).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tmp-objdir.c

@@ -188,7 +188,7 @@ static int read_dir_paths(struct string_list *out, const char *path)
 		return -1;
 
 	while ((de = readdir(dh)))
-		if (!is_dot_or_dotdot(de->d_name))
+		if (de->d_name[0] != '.')
 			string_list_append(out, de->d_name);
 
 	closedir(dh);