Remove VTK legacy functions

[jasjuang]

Recently VTK removes some legacy functions that causes PCL to stop compiling.

Kitware/VTK@fc2ac65

The fix is applied according to the suggestion of the VTK devs.

I tested and it compiles and runs without a problem on Ubuntu 16.04 latest PCL.

[taketwo]

#2112 already takes care of this, however there the function calls are not removed, instead conditionally disabled with #if VTK_RENDERING_BACKEND_OPENGL_VERSION < 2. Do you think it is wrong? Also, what the "suggestion of the VTK devs" that you are referring to?

[jasjuang]

@taketwo "suggestion of the VTK devs" is referring to the comments mentioned in the very bottom of Kitware/VTK@fc2ac65

You are actually right, #2112 does take care of it and using #if VTK_RENDERING_BACKEND_OPENGL_VERSION < 2 might actually provide additional backwards compatibility on old old VTK.

What is the status of #2112? If you plan to merge #2112 soon feel free to close this PR. However if it's going to take some time I can push the #if VTK_RENDERING_BACKEND_OPENGL_VERSION < 2 change to get PCL to compile again.

[taketwo]

The author of #2112 did not reply for a while, so I pushed an additional commit addressing remaining review issues. Once the CI pipelines are finished I'll merge.