[dia] Don't save empty meta info property

[Hans Breuer <hans src gnome org>]

commit 623a84c7a266fae792543852f67f040df1e3ce57
Author: Hans Breuer <hans breuer org>
Date:   Sat Mar 16 17:59:59 2013 +0100

    Don't save empty meta info property

 lib/object.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/lib/object.c b/lib/object.c
index 892fc0b..c4ce4f5 100644
--- a/lib/object.c
+++ b/lib/object.c
@@ -768,7 +768,7 @@ object_save(DiaObject *obj, ObjectNode obj_node)
                 &obj->position);
   data_add_rectangle(new_attribute(obj_node, "obj_bb"),
                     &obj->bounding_box);
-  if (obj->meta)
+  if (obj->meta && g_hash_table_size (obj->meta) > 0)
     data_add_dict (new_attribute(obj_node, "meta"), obj->meta);
 }