OpenVR Plugin: Fix compile error
QVTKOpenGLWidget was deprecated in VTK for some time, was removed in 9_0_0, and has been renamed to QVTKOpenGLStereoWidget.
Edited by Tiffany Chhim
QVTKOpenGLWidget was deprecated in VTK for some time, was removed in 9_0_0, and has been renamed to QVTKOpenGLStereoWidget.