setup: include a dummy $PATH in the custom environment used by build.py This is required for building with pypiwin32, the pip-installable replacement for pywin32.

shelve: move unshelve-finishing logic to a separate function Finishing unshelve involves two steps now: - stripping a changelog - aborting a transaction Obs-based shelve will not require these things, so isolating this logic into a separate function where the normal/obs-shelve branching is going to be implemented seems to be like a nice idea. Behavior-wise this change moves 'unshelvecleanup' from being between changelog stripping and transaction abortion to being after them. I don't think this has any negative effects.

shelve: move file-forgetting logic to a separate function This is just a readability improvement.