Fixed the failing IECoreGL::ColorTexture test cases.
Fixed the failing IECoreGL::ColorTexture test cases.

appleseedhq/cortex,lento/cortex,appleseedhq/cortex,hradec/cortex,hradec/cortex,davidsminor/cortex,davidsminor/cortex,goddardl/cortex,lento/cortex,appleseedhq/cortex,goddardl/cortex,danieldresser/cortex,danieldresser/cortex,davidsminor/cortex,goddardl/cortex,danieldresser/cortex,lento/cortex,danieldresser/cortex,davidsminor/cortex,hradec/cortex