Removing SVX_DLLPRIVATE from GetInteractionHandles() and from DragMoveCustomShapeHdl()

[Regina Henschel]

Hi all,

for my ask for help in 
https://lists.freedesktop.org/archives/libreoffice/2019-May/082739.html 
Stephan has mentioned three ways for getting my unit test work
- using a different way --- I have no better idea.
- use gb_CppunitTest_use_library_objects --- That does not work.
- remove SVX_DLLPRIVATE --- That works.

I have changed the patch in https://gerrit.libreoffice.org/#/c/72229/4 
accordingly.

Is that OK? Or does it produce problems in other areas? I think, the 
author of that lines had a reason to restrict a public function with 
SVX_DLLPRIVATE?

Kind regards
Regina