Fix crash when using multiple GPU
Fix crash when using multiple GPU

monsieurzhang/OpenNMT,da03/OpenNMT,OpenNMT/OpenNMT,monsieurzhang/OpenNMT,OpenNMT/OpenNMT,monsieurzhang/OpenNMT,jsenellart-systran/OpenNMT,jungikim/OpenNMT,da03/OpenNMT,jsenellart-systran/OpenNMT,OpenNMT/OpenNMT,jungikim/OpenNMT,jsenellart-systran/OpenNMT,jsenellart/OpenNMT,jsenellart/OpenNMT,da03/OpenNMT,jsenellart/OpenNMT,jungikim/OpenNMT