Fault tolerent job default global learning rate is not set
Created by: typhoonzero
Running fault tolerent job with pserver written in go currently go to this line
This is because the default learning rate for v2 API is always "poly": https://github.com/PaddlePaddle/Paddle/blob/develop/python/paddle/trainer_config_helpers/optimizers.py#L362 , and the pserver does not support it yet. should implement "poly" method.