message: Update tvl1_optical_flow.cpp
  repair broken cmdline param for cpu/gpu mode
diff: @@ -105,7 +105,7 @@ int main(int argc, const char* argv[])
  string fname1 = cmd.get<string>("r");
  string vdofile = cmd.get<string>("v");
  string outpath = cmd.get<string>("o");
  - bool useCPU = cmd.get<bool>("s");
  + bool useCPU = cmd.get<bool>("m");
  bool useCamera = cmd.get<bool>("c");
  int inputName = cmd.get<int>("c");
  