COMP: Fix "unused-local-typedefs" warning in LandmarkBasedTransformInitializer

This commit fixes the following Slicer warning:

// -------
In file included from /path/to/ITKv4/Modules/Core/Transform/include/itkLandmarkBasedTransformInitializer.h:188:0,
                 from /path/to/Slicer/Modules/CLI/FiducialRegistration/FiducialRegistration.cxx:7:
/path/to/ITKv4/Modules/Core/Transform/include/itkLandmarkBasedTransformInitializer.hxx: In member function ‘void itk::LandmarkBasedTransformInitializer<TTransform, TFixedImage, TMovingImage>::InternalInitializeTransform(itk::LandmarkBasedTransformInitializer<TTransform, TFixedImage, TMovingImage>::VersorRigid3DTransformType*)’:
/path/to/ITKv4/Modules/Core/Transform/include/itkLandmarkBasedTransformInitializer.hxx:252:65: warning: typedef ‘RotationCenterType’ locally defined but not used [-Wunused-local-typedefs]
   typedef typename VersorRigid3DTransformType::CenterType       RotationCenterType;
// -------