[FIX] hr_holidays: allocation by tag

Revision 1e90257e58 removed hierarchy in
hr.employee.category model. Indeed they are used and displayed like tags
and not like hierarchical categories anymore.

However the allocation by tag was still using the childof operator
to go through hierarchy. No need to do that anymore.

addons/hr_holidays/hr_holidays.py

@@ -426,7 +426,7 @@ class hr_holidays(osv.osv):
                 self._create_resource_leave(cr, uid, [record], context=context)
                 self.write(cr, uid, ids, {'meeting_id': meeting_id})
             elif record.holiday_type == 'category':
-                emp_ids = obj_emp.search(cr, uid, [('category_ids', 'child_of', [record.category_id.id])])
+                emp_ids = record.category_id.employee_ids.ids
                 leave_ids = []
                 batch_context = dict(context, mail_notify_force_send=False)
                 for emp in obj_emp.browse(cr, uid, emp_ids, context=context):