read-cache.c: remove the_* from index_has_changes()

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/merge-recursive.c b/merge-recursive.c
index a596d95..df00896 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3412,7 +3412,7 @@ int merge_trees(struct merge_options *o,
 	int code, clean;
 	struct strbuf sb = STRBUF_INIT;
 
-	if (!o->call_depth && index_has_changes(istate, head, &sb)) {
+	if (!o->call_depth && repo_index_has_changes(o->repo, head, &sb)) {
 		err(o, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
 		    sb.buf);
 		return -1;