Make track_tree_refs void.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

tree.c

@@ -144,7 +144,7 @@ struct tree *lookup_tree(const unsigned char *sha1)
 	return (struct tree *) obj;
 }
 
-static int track_tree_refs(struct tree *item)
+static void track_tree_refs(struct tree *item)
 {
 	int n_refs = 0, i;
 	struct object_refs *refs;
@@ -174,7 +174,6 @@ static int track_tree_refs(struct tree *item)
 		refs->ref[i++] = obj;
 	}
 	set_object_refs(&item->object, refs);
-	return 0;
 }
 
 int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)