addERP5Tool might be clever now, and avoids recreating portal_activities
if it already exists, but the line just after should *not* be run if
the tool already exists, or else we simply clear all activities generating
during BT5 install.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@43012 20353a03-c40f-0410-a6d1-a30d3c3de9de