[MERGE] Make accessing a branch.tags.get_tag_dict use a smart[er] method rather than VFS calls and real objects.

[Bundle Buggy]

Bundle Buggy has detected this merge request.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C1236311834.10834.1.camel%40lifeless-64%3E
Project: Bazaar