Merge branch 'mh/simplify-repack-without-refs'

"git remote update --prune" to drop many refs has been optimized.

* mh/simplify-repack-without-refs:
  sort_string_list(): rename to string_list_sort()
  prune_remote(): iterate using for_each_string_list_item()
  prune_remote(): rename local variable
  repack_without_refs(): make the refnames argument a string_list
  prune_remote(): sort delete_refs_list references en masse
  prune_remote(): initialize both delete_refs lists in a single loop
  prune_remote(): exit early if there are no stale references

connect.c

@@ -93,7 +93,7 @@ static void annotate_refs_with_symref_info(struct ref *ref)
 		parse_one_symref_info(&symref, val, len);
 		feature_list = val + 1;
 	}
-	sort_string_list(&symref);
+	string_list_sort(&symref);
 
 	for (; ref; ref = ref->next) {
 		struct string_list_item *item;