Checkmk Werk 10042: Fix exception caused by autochecks with integers as items

ID: 10042 Title: Fix exception caused by autochecks with integers as items Component: Core & setup Level: 1 Class: Bug fix Version: 1.7.0i1 The calculation of check parameters during activate changes or checking could cause an exception like "TypeError: expected string or buffer" when a discovery function of a check created services using integers as items instead of strings.