Fixed clang analyzer warnings about dereferences
Fixed clang analyzer warnings about dereferences

Added default case to switch so that returned
pointer value is null instead of undefined.
Also initialized some pointers to null.
Analyzer still warns about improbable paths
that would deref null, but that's better than
derefing a random pointer at least.

Change-Id: I0fd5bc9c975411379994a0fb1002676ba759c85d

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