[MERGE] Fix in Knit._check_should_delta

[Ian Clatworthy]

Ian Clatworthy has voted approve.
Status is now: Approved


For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3C498237BE.1030408%40arbash-meinel.com%3E
Project: Bazaar