Fixed bug #361 again (parent_id of log entry cr_items point to case's object), this time providing an upgrade script, changing the parent_id of existing log entries, and fixing the case deletion proc to delete cases properly given the parent_id.
bug 361: making cr_items.parent_id of case log entries be the object_id of the object governed by the case, just like for the acs_object.context_id of the case