fix a bug in Common::AvoidInf.
fix a bug in Common::AvoidInf.

olofer/LightGBM,huanzhang12/LightGBM,huanzhang12/LightGBM,microsoft/LightGBM,olofer/LightGBM,microsoft/LightGBM,olofer/LightGBM,henry0312/LightGBM,Allardvm/LightGBM,Allardvm/LightGBM,Allardvm/LightGBM,henry0312/LightGBM,microsoft/LightGBM,wxchan/LightGBM,wxchan/LightGBM,wxchan/LightGBM,henry0312/LightGBM,huanzhang12/LightGBM,Allardvm/LightGBM,Laurae2/LightGBM,Laurae2/LightGBM,Laurae2/LightGBM,wxchan/LightGBM,Laurae2/LightGBM,huanzhang12/LightGBM,wxchan/LightGBM,henry0312/LightGBM,Laurae2/LightGBM,huanzhang12/LightGBM,olofer/LightGBM,henry0312/LightGBM,microsoft/LightGBM,microsoft/LightGBM,Allardvm/LightGBM,olofer/LightGBM