zlib: remove empty if statements
zlib: remove empty if statements

Change-Id: I55a363559104f0f726945255b710e1e6549b7b49

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