Do not reset scissors use after each render

Rendering/OpenGL2/vtkOpenGLCamera.cxx

@@ -64,7 +64,6 @@ void vtkOpenGLCamera::Render(vtkRenderer* ren)
   {
     ostate->vtkglScissor(this->ScissorRect.GetX(), this->ScissorRect.GetY(),
       this->ScissorRect.GetWidth(), this->ScissorRect.GetHeight());
-    this->UseScissor = false;
   }
   else
   {
@@ -96,7 +95,6 @@ void vtkOpenGLCamera::UpdateViewport(vtkRenderer* ren)
   {
     ostate->vtkglScissor(this->ScissorRect.GetX(), this->ScissorRect.GetY(),
       this->ScissorRect.GetWidth(), this->ScissorRect.GetHeight());
-    this->UseScissor = false;
   }
   else
   {