Use start date to guess the year for which the reference will be computed, this allows testing reference generation for non-current year (start_date is verified to be the same as now in regular use).
Remove an unneeded date cast in catalog parameters.

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25003 20353a03-c40f-0410-a6d1-a30d3c3de9de