Checkmk Werk 14747: Fix duplicate history log while processing spoolfiles

ID: 14747 Title: Fix duplicate history log while processing spoolfiles Component: Notifications Level: 1 Class: Bug fix Version: 2.2.0i1 Werk #13114 fixed missing history log entries for direct local delivery of notifications. If notification spooling was used afterwards, there was a duplicate message logged. Now only one message will be logged also for spoolfiles.