Code review comment for lp:~mbp/bzr/cleanup

Hmm. I think this is fine, although it feels half-done to me, because many objects that want cleanup management (e.g. Command, Commit) also want a robust way to run a method and then the cleanups.

So I'm ok with this landing if you find it useful for something, but I anticipate that it will soon grow some equivalent to the run method of OperationWithCleanups too (or perhaps _do_with_cleanups will be promoted to a public function?). Also, the cleanup.py module docstring is pretty focused on the robust-run-with-cleanups use case, so perhaps if the scope is growing to more general cleanup-list management then the docstring should be updated to reflect that.