list-objects: move tag processing into its own function

Move processing of tags into its own function to make the logic easier
to extend when we're going to implement filtering for tags. No change in
behaviour is expected from this commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

list-objects.c

@@ -213,6 +213,14 @@ static void process_tree(struct traversal_context *ctx,
 	free_tree_buffer(tree);
 }
 
+static void process_tag(struct traversal_context *ctx,
+			struct tag *tag,
+			const char *name)
+{
+	tag->object.flags |= SEEN;
+	ctx->show_object(&tag->object, name, ctx->show_data);
+}
+
 static void mark_edge_parents_uninteresting(struct commit *commit,
 					    struct rev_info *revs,
 					    show_edge_fn show_edge)
@@ -334,8 +342,7 @@ static void traverse_trees_and_blobs(struct traversal_context *ctx,
 		if (obj->flags & (UNINTERESTING | SEEN))
 			continue;
 		if (obj->type == OBJ_TAG) {
-			obj->flags |= SEEN;
-			ctx->show_object(obj, name, ctx->show_data);
+			process_tag(ctx, (struct tag *)obj, name);
 			continue;
 		}
 		if (!path)