handle os.path.walk/os.walk for Python 3
handle os.path.walk/os.walk for Python 3

yyt030/pyzmq,caidongyun/pyzmq,dash-dash/pyzmq,yyt030/pyzmq,dash-dash/pyzmq,Mustard-Systems-Ltd/pyzmq,Mustard-Systems-Ltd/pyzmq,dash-dash/pyzmq,swn1/pyzmq,Mustard-Systems-Ltd/pyzmq,swn1/pyzmq,caidongyun/pyzmq,ArvinPan/pyzmq,caidongyun/pyzmq,yyt030/pyzmq,ArvinPan/pyzmq,swn1/pyzmq,ArvinPan/pyzmq