Fixed Windows build issue in FromMayaPlugConverter.
Fixed Windows build issue in FromMayaPlugConverter.

Many thanks to Sun HaoHui for finding it.

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