Merge branch 'jx/pack-redundant-on-single-pack'

"git pack-redandant" when there is only one packfile used to crash,
which has been corrected.

* jx/pack-redundant-on-single-pack:
  pack-redundant: fix crash when one packfile in repo

builtin/pack-redundant.c

@@ -473,6 +473,12 @@ static void cmp_local_packs(void)
 {
 	struct pack_list *subset, *pl = local_packs;
 
+	/* only one packfile */
+	if (!pl->next) {
+		llist_init(&pl->unique_objects);
+		return;
+	}
+
 	while ((subset = pl)) {
 		while ((subset = subset->next))
 			cmp_two_packs(pl, subset);