Restore previous behaviour for ERP5Type_getSecurityCategoryFromArrow, and introduce a new script, ERP5Type_getSecurityCategoryFromAcquiredArrow, which uses acquisition. This is more consistent with category API, I'll post more explanations on the list.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@19639 20353a03-c40f-0410-a6d1-a30d3c3de9de