Checkmk Werk 14401: crash in legacy plugins with empty details

ID: 14401 Title: crash in legacy plugins with empty details Component: Checks & agents Level: 1 Class: Bug fix Version: 2.2.0i1 Some legacy plugins can print a newline indicating details to come and not follow up with any details. This lead to a crash with the message "ValueError ('details' must be non-empty str or None, got )". This has been fixed. No user interaction required.