[MERGE] Fix InterBranch.pull tests.

[Ian Clatworthy]

Ian Clatworthy has voted tweak.
Status is now: Conditionally approved
Comment:
Please add a comment to test_pull explaining where most of the code came 
from.

It might also be worth capturing some of the conversation between you 
and Robert - 
http://thread.gmane.org/gmane.comp.version-control.bazaar-ng.general/55343 
- in some comments in InterBranch.pull().

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C20090330192444.2A1BE1D35A%40ganieda.vernstok.nl%3E
Project: Bazaar