find_symref(): convert local variable "unused" to object_id

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

upload-pack.c

@@ -746,11 +746,11 @@ static int find_symref(const char *refname, const struct object_id *oid,
 {
 	const char *symref_target;
 	struct string_list_item *item;
-	unsigned char unused[20];
+	struct object_id unused;
 
 	if ((flag & REF_ISSYMREF) == 0)
 		return 0;
-	symref_target = resolve_ref_unsafe(refname, 0, unused, &flag);
+	symref_target = resolve_ref_unsafe(refname, 0, unused.hash, &flag);
 	if (!symref_target || (flag & REF_ISSYMREF) == 0)
 		die("'%s' is a symref but it is not?", refname);
 	item = string_list_append(cb_data, refname);