Deprecate QMutex in recursive mode
Use QRecursiveMutex instead.
Pick-to: 5.15 Change-Id: I862fc2b3143deeb5c96dc8d445be5f9fa2535670 Reviewed-by: Volker Hilsheimer volker.hilsheimer@qt.io Reviewed-by: Mårten Nordheim marten.nordheim@qt.io (cherry picked from commit 0e681064)