[merge][#295350] fix another "revision not present" in stacked repositories

[Bundle Buggy]

Bundle Buggy has detected this merge request.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Ce01316480811200433l1ed1082dr4f1e2c729e973cdb%40mail.gmail.com%3E
Project: Bazaar