readme fix

Edmond Yoo

2018-09-06 595a5ea1f6fed9351862a2708a64d7fc10a7cf6a

 src/darknet.c

@@ -377,6 +377,7 @@
#else
    if(gpu_index >= 0){
        cuda_set_device(gpu_index);
        check_error(cudaSetDeviceFlags(cudaDeviceScheduleBlockingSync));
    }
#endif