Comment 4 for bug 237297

Bug 238869 also mentions this happening when connecting to Launchpad.

It looks like <http://tartarus.org/~simon/putty-snapshots/htmldoc/Chapter2.html> Putty will prompt to accept the key when run interactively, but it's not doing it here. So the bzr bug is that we're invoking it in such a way that it can't do this. I'm not sure if that's because we're providing perhaps a --batch option, or because when it's run as a subprocess it simply can't ask the user.