Transformation is an optional property of XShape,
rATransformation can refer to an empty Any.

results in warnings like this, e.g. when you add a legend:
> warn:chart2:27587:1:chart2/source/view/main/ShapeFactory.cxx:2135:
> Exception caught. Type: N3com3sun4star3uno9ExceptionE, Message:

set Transformation property only if needed

Change-Id: I1edae0a984f8264a6a0638b90a7197e316832c02
Reviewed-on: https://gerrit.libreoffice.org/29527Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>