Reference to nonexistent function when building examples

Fresh build, set "VTKm_ENABLE_CUDA" and "VTKm_ENABLE_EXAMPLES" to ON.

Build fails with the following error:

/home/nleaf/projects/vtk-m/vtkm/rendering/MapperGL.cxx: In member function ‘bool vtkm::rendering::{anonymous}::MapColorAndVerticesInvokeFunctor::operator()(Device) const’: /home/nleaf/projects/vtk-m/vtkm/rendering/MapperGL.cxx:182:41: error: ‘const class vtkm::cont::ColorTable’ has no member named ‘GetHandleForExecution’; did you mean ‘PrepareForExecution’? auto colorHandle = this->ColorTable.GetHandleForExecution();