[MERGE] Use Repository.get_revision_delta() in missing rather than doing the delta

[Ian Clatworthy]

Ian Clatworthy has voted approve.
Status is now: Approved


For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C20090214182425.96BB4572E4%40charis.vernstok.nl.vernstok.nl%3E
Project: Bazaar