vtkXMLPStructuredGridWriter::GetDefaultFileExtension() is unnecessarily protected
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
vtkXMLPStructuredGridWriter::GetDefaultFileExtension(), which simply returns "pvts" is unnecessarily protected. This is inconsistent with vtkXMLPUnstructuredGridWriter and vtkXMLPPolyDataWriter, both of which expose GetDefaultExtension() publicly.