- Catch by value exception in `Testing/VTKITKVectorReader.cxx`

```cpp
warning: catching polymorphic type ‘class itk::ExceptionObject’ by value [-Wcatch-value=]
```

- unused variable in vtkAddon/vtkOpenGLShaderComputation.cxx

```cpp
/Libs/vtkAddon/vtkOpenGLShaderComputation.cxx:423:10: warning: unused variable ‘status’ [-Wunused-variable]
   GLenum status;
          ^~~~~~
```

From: Pablo Hernandez-Cerdan <pablo.hernandez.cerdan@outlook.com>

git-svn-id: http://svn.slicer.org/Slicer4/trunk@27994 3bd1e089-480b-0410-8dfb-8563597acbee