[Zope] clean up Data.fs?

[Kyler B. Laird]

It turned out to be a problem with my custom user
folder product.  Perhaps this can help someone
later...

I was caching some information in my product
using a global variable that started with _v_.
Moving this to be self._v_cache solved the
problem.

My *guess* is that something in the transaction
machinery fails when there is data not tucked
away in the proper place.  Because I had to
authenticate to use Undo and Versions, my info
was in this variable.

So, the lesson is that I should avoid global
variables in products, even if they appear to
work otherwise.

Thank you.

--kyler