Fix backward compatibility.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@45413 20353a03-c40f-0410-a6d1-a30d3c3de9de

product/ERP5Type/Core/SQLCache.py

+# Simple, stupid backward compatibility with existing persistent instances.
+# Makes it possible to upgrade erp5_core on old sites (otherwise, saving to
+# portal_trash fails).
+from Products.ERP5Type.XMLObject import XMLObject as SQLCache
+