Cannot uninstall 'httplib2'. It is a distutils installed project and thus we cannot accurately deter

Cannot uninstall ‘httplib2’. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
在安装Tensor2Tensor时，某依赖包的版本过旧，不支持新的依赖包，导致安装失败，遂卸载掉这个旧版本的httplib2，但是提示卸载失败。所以直接强制升级！

sudo pip install --ignore-installed httplib2
#或
sudo pip install3 --ignore-installed httplib2