make sure glsl extensions are requested at the start of a shader
make sure glsl extensions are requested at the start of a shader

Change-Id: Ib225dde13078726b8d7a989345c16cf7244d4b76

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