The 3.3 branch is not affected as the f0833e6ff2d2 changeset was never merged into that branch.

In the default branch the exception stops appearing after commit 79e2f5bbc30c: "Issue #18214: Improve finalization of Python modules to avoid setting their globals to None, in most cases." This changeset is also part of the current 3.4 tip (19172062e5c0), so 3.4 tip does not display the buggy behaviour. Judging by the commit message, that commit also supersedes the attached patch as it at least prevents the visible symptoms. I am not sure if there still might be a deeper issue that is hidden by the changeset as Terry suggested.