[IMP] unlink ir.action.todo which are related to actions which will be deleted

In order to module uninstall work properly
--> Unlink ir.action.todo which are related to actions which will be deleted. on-delete cascade will not work on ir.actions.actions so we will need to do it manually
--> Improve need_action_data method also to avoid error.
[Task] : https://openerp.my.openerp.com/web#id=4390&view_type=form&model=project.task&menu_id=3942&action=327
[Pad] : https://pad.odoo.com/p/r.IipxlDnM5havhDEu