* modify activity_restart_check constraint so that it's only taken into account when activity_restart_check is equal to 1.
*change also types of date, instead of string use type date

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25413 20353a03-c40f-0410-a6d1-a30d3c3de9de