Merge topic 'revert_dpi_changes'

00a209da Revert "Set VTK DPI in the render window set in QVTKOpenGLWidget"

Acked-by: Kitware Robot <kwrobot@kitware.com>
Reviewed-by: Utkarsh Ayachit <utkarsh.ayachit@kitware.com>
Reviewed-by: Marcus D. Hanwell <marcus.hanwell@kitware.com>
Merge-request: !2668