Fix the bug that user couldn't choose to use gpu whether or not (!17) · 合并请求 · PaddlePaddle / PaddleHub

Fix the bug that user couldn't choose to use gpu whether or not !17

Created by: Steffy-zxf

As the demo text-classification use the GPU to run the model, it isn't suitable. We fix it that user can choose the gpu or not to run the model.