Message 152675 - Python tracker

> Note that my proposed syntax does not allow something equivalent to {'': [etc.]} in
> distutils, i.e. package data for top-level modules.  I think this is okay: modules should
> not install data in their installation dir.  I don’t think it was widely used

I tested: This construct was allowed but did not actually cause any file to be installed (i.e. no crash, no-op), so we’re not removing any functionality here.