Old header.LGPL21 header was used at some files. Replase those with
new header.LGPL one
Remove old header.LGPL21
Task-number: QTBUG-57147
Change-Id: I650e39024ed4876bba27e954c7d61fdb025b46ef
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: Lars Knoll <lars.knoll@qt.io>