Another compile fix error

AlexeyAB

2018-02-12 9c847647a1f3c257aaa8c0d4ec718e68888984ba

 src/network_kernels.cu

@@ -114,6 +114,7 @@
    state.truth = *net.truth_gpu;
    state.train = 1;
    forward_network_gpu(net, state);
   cudaStreamSynchronize(get_cuda_stream());
    backward_network_gpu(net, state);
}