[FIX] mail: allow to set own batch size for mass mailing

addons/mail/wizard/mail_compose_message.py

@@ -221,7 +221,9 @@ class mail_compose_message(osv.TransientModel):
             else:
                 res_ids = [wizard.res_id]
 
-            sliced_res_ids = [res_ids[i:i + self._batch_size] for i in range(0, len(res_ids), self._batch_size)]
+            batch_size = self.pool['ir.config_parameter'].get_param(cr, SUPERUSER_ID, 'mail.batch_size') or self._batch_size
+
+            sliced_res_ids = [res_ids[i:i + batch_size] for i in range(0, len(res_ids), batch_size)]
             for res_ids in sliced_res_ids:
                 all_mail_values = self.get_mail_values(cr, uid, wizard, res_ids, context=context)
                 for res_id, mail_values in all_mail_values.iteritems():