Moved OSLShader shading engine cache into anonymous namespace.
Moved OSLShader shading engine cache into anonymous namespace.

We don't want to expose it as part of the public API.

davidsminor/gaffer,andrewkaufman/gaffer,cedriclaunay/gaffer,boberfly/gaffer,ImageEngine/gaffer,goddardl/gaffer,hradec/gaffer,cedriclaunay/gaffer,GafferHQ/gaffer,ImageEngine/gaffer,ivanimanishi/gaffer,hradec/gaffer,boberfly/gaffer,goddardl/gaffer,GafferHQ/gaffer,chippey/gaffer,appleseedhq/gaffer,lucienfostier/gaffer,davidsminor/gaffer,ImageEngine/gaffer,cedriclaunay/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,johnhaddon/gaffer,andrewkaufman/gaffer,ivanimanishi/gaffer,goddardl/gaffer,johnhaddon/gaffer,boberfly/gaffer,boberfly/gaffer,GafferHQ/gaffer,hradec/gaffer,johnhaddon/gaffer,davidsminor/gaffer,chippey/gaffer,appleseedhq/gaffer,GafferHQ/gaffer,cedriclaunay/gaffer,chippey/gaffer,lucienfostier/gaffer,ivanimanishi/gaffer,appleseedhq/gaffer,hradec/gaffer,davidsminor/gaffer,lucienfostier/gaffer,GafferHQ/gaffer,goddardl/gaffer,appleseedhq/gaffer,andrewkaufman/gaffer,andrewkaufman/gaffer,chippey/gaffer,johnhaddon/gaffer,hradec/gaffer,lucienfostier/gaffer,ImageEngine/gaffer,ivanimanishi/gaffer