Comment 8 for bug 403857

The reason we give PermissionDenied in situations where NoSuchFile might seem more reasonable have, IIRC, to do with the client suggesting --create-prefix in some situations where --create-prefix will not in fact work. We should revisit this, and consider fixing the client, if that's possible.

There's also the issue that the message we give is the same for attempts to create and attempts to read non .bzr filenames at the top level of a branch, and that's a bit silly. Not sure if this is directly related though.