Code review comment for lp:~gz/bzr/require_unicode_committer_614593

Thanks John, that's just the kind of feedback I wanted. I'll move the guard further in as you suggest.

Doing that, just realised the test I added doesn't actually fail unless I add a format="dirstate-with-subtree" like the testament tests have. This suggests it should be in... per_repository.test_commit_builder instead maybe?