problem of inconsistent-missing-override

[jacquesqiao]

I build the newest develop branch of Paddle on my macbook and get the error below:
May be it's because I update my osx system last day. But I think this problem should be resolved.

/Users/qiaolongfei/project/paddle-test/paddle/gserver/gradientmachines/NeuralNetwork.cpp:312:16: error: 'start' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
  virtual void start() {
               ^
/Users/qiaolongfei/project/paddle-test/paddle/gserver/evaluators/Evaluator.h:55:16: note: overridden virtual function is here
  virtual void start() {
               ^
/Users/qiaolongfei/project/paddle-test/paddle/gserver/gradientmachines/NeuralNetwork.cpp:318:16: error: 'finish' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
  virtual void finish() {