Fixup bugs in vtkBoxClipDataSet.
Fixup bugs in vtkBoxClipDataSet.

There were some copy/paste errors and an uninitialized
traversal causing the clipped output to produce a data set
with more cell types than cell connections.

Change-Id: Ia8918b58f925c075eed10e8157406759cd789f42

gram526/VTK,mspark93/VTK,sankhesh/VTK,sankhesh/VTK,jmerkow/VTK,sumedhasingla/VTK,biddisco/VTK,msmolens/VTK,msmolens/VTK,jmerkow/VTK,mspark93/VTK,msmolens/VTK,keithroe/vtkoptix,SimVascular/VTK,demarle/VTK,SimVascular/VTK,berendkleinhaneveld/VTK,johnkit/vtk-dev,ashray/VTK-EVM,jmerkow/VTK,sankhesh/VTK,sankhesh/VTK,SimVascular/VTK,gram526/VTK,mspark93/VTK,jmerkow/VTK,demarle/VTK,ashray/VTK-EVM,jmerkow/VTK,berendkleinhaneveld/VTK,johnkit/vtk-dev,jmerkow/VTK,keithroe/vtkoptix,SimVascular/VTK,berendkleinhaneveld/VTK,hendradarwin/VTK,sumedhasingla/VTK,gram526/VTK,ashray/VTK-EVM,johnkit/vtk-dev,candy7393/VTK,demarle/VTK,candy7393/VTK,gram526/VTK,sumedhasingla/VTK,johnkit/vtk-dev,candy7393/VTK,sankhesh/VTK,candy7393/VTK,msmolens/VTK,hendradarwin/VTK,sumedhasingla/VTK,demarle/VTK,berendkleinhaneveld/VTK,jmerkow/VTK,candy7393/VTK,sumedhasingla/VTK,msmolens/VTK,mspark93/VTK,biddisco/VTK,biddisco/VTK,demarle/VTK,keithroe/vtkoptix,gram526/VTK,keithroe/vtkoptix,gram526/VTK,hendradarwin/VTK,sankhesh/VTK,biddisco/VTK,hendradarwin/VTK,ashray/VTK-EVM,candy7393/VTK,biddisco/VTK,mspark93/VTK,gram526/VTK,biddisco/VTK,berendkleinhaneveld/VTK,mspark93/VTK,sumedhasingla/VTK,sumedhasingla/VTK,keithroe/vtkoptix,ashray/VTK-EVM,ashray/VTK-EVM,berendkleinhaneveld/VTK,johnkit/vtk-dev,mspark93/VTK,berendkleinhaneveld/VTK,demarle/VTK,candy7393/VTK,biddisco/VTK,SimVascular/VTK,sankhesh/VTK,hendradarwin/VTK,keithroe/vtkoptix,johnkit/vtk-dev,SimVascular/VTK,msmolens/VTK,SimVascular/VTK,demarle/VTK,ashray/VTK-EVM,jmerkow/VTK,gram526/VTK,candy7393/VTK,msmolens/VTK,keithroe/vtkoptix,sumedhasingla/VTK,SimVascular/VTK,hendradarwin/VTK,johnkit/vtk-dev,mspark93/VTK,keithroe/vtkoptix,demarle/VTK,msmolens/VTK,hendradarwin/VTK,sankhesh/VTK,ashray/VTK-EVM