Cleaned up warnings of the form:

   warning C4275: non dll-interface class 'google::protobuf::Message' used
   as base for dll-interface class 'paraview_protobuf..'

- The header order in vtkSMMessage.h was accidentally changed fixed that.
- `vtk_protobuf.h.in` was using incorrect header/var to determine is using
  shared libs, fixed that.
- removed duplicate defines for PROTOBUF_USE_DLLS