In Qt 5.15 the comparison operator for QVariant got deprecated.
Fix the warning by substituting comparison operator by custom
method.
Change-Id: I1a5c4ab6742a6d8d85f6cff5a73d5f49c2d5aa73
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>