Don't throw and error when selection filter is given an empty input.
Don't throw and error when selection filter is given an empty input.

Thanks Andreas Buykx for the patch.

Change-Id: I678061ce17170efbdcf8b1d3ccb3c011e3e0193c

candy7393/VTK,ashray/VTK-EVM,ashray/VTK-EVM,johnkit/vtk-dev,ashray/VTK-EVM,msmolens/VTK,jmerkow/VTK,keithroe/vtkoptix,biddisco/VTK,candy7393/VTK,SimVascular/VTK,msmolens/VTK,SimVascular/VTK,collects/VTK,gram526/VTK,spthaolt/VTK,demarle/VTK,keithroe/vtkoptix,aashish24/VTK-old,mspark93/VTK,sankhesh/VTK,jmerkow/VTK,candy7393/VTK,hendradarwin/VTK,keithroe/vtkoptix,jmerkow/VTK,aashish24/VTK-old,SimVascular/VTK,candy7393/VTK,hendradarwin/VTK,berendkleinhaneveld/VTK,johnkit/vtk-dev,ashray/VTK-EVM,SimVascular/VTK,jmerkow/VTK,johnkit/vtk-dev,gram526/VTK,berendkleinhaneveld/VTK,msmolens/VTK,cjh1/VTK,biddisco/VTK,ashray/VTK-EVM,aashish24/VTK-old,aashish24/VTK-old,biddisco/VTK,sumedhasingla/VTK,jmerkow/VTK,johnkit/vtk-dev,SimVascular/VTK,gram526/VTK,cjh1/VTK,demarle/VTK,cjh1/VTK,johnkit/vtk-dev,berendkleinhaneveld/VTK,candy7393/VTK,collects/VTK,keithroe/vtkoptix,jmerkow/VTK,candy7393/VTK,sankhesh/VTK,mspark93/VTK,sumedhasingla/VTK,mspark93/VTK,hendradarwin/VTK,spthaolt/VTK,aashish24/VTK-old,sankhesh/VTK,keithroe/vtkoptix,keithroe/vtkoptix,SimVascular/VTK,berendkleinhaneveld/VTK,spthaolt/VTK,biddisco/VTK,sankhesh/VTK,spthaolt/VTK,biddisco/VTK,mspark93/VTK,jmerkow/VTK,msmolens/VTK,spthaolt/VTK,hendradarwin/VTK,gram526/VTK,collects/VTK,mspark93/VTK,sumedhasingla/VTK,mspark93/VTK,demarle/VTK,collects/VTK,johnkit/vtk-dev,sumedhasingla/VTK,sankhesh/VTK,ashray/VTK-EVM,keithroe/vtkoptix,berendkleinhaneveld/VTK,sumedhasingla/VTK,johnkit/vtk-dev,gram526/VTK,sumedhasingla/VTK,sankhesh/VTK,cjh1/VTK,sankhesh/VTK,spthaolt/VTK,cjh1/VTK,keithroe/vtkoptix,sumedhasingla/VTK,biddisco/VTK,gram526/VTK,cjh1/VTK,collects/VTK,msmolens/VTK,sankhesh/VTK,demarle/VTK,mspark93/VTK,sumedhasingla/VTK,jmerkow/VTK,demarle/VTK,demarle/VTK,demarle/VTK,candy7393/VTK,demarle/VTK,hendradarwin/VTK,collects/VTK,biddisco/VTK,hendradarwin/VTK,SimVascular/VTK,spthaolt/VTK,gram526/VTK,SimVascular/VTK,msmolens/VTK,berendkleinhaneveld/VTK,msmolens/VTK,candy7393/VTK,hendradarwin/VTK,berendkleinhaneveld/VTK,msmolens/VTK,mspark93/VTK,ashray/VTK-EVM,gram526/VTK,aashish24/VTK-old,ashray/VTK-EVM