买的阿里云机器，git clone 不下来，报错：
A TLS packet with unexpected length was received
摸不到头脑，Google 之，在 StackOverFlow 上面找到一个神奇的答案：
If you are in china,may be you should set proxy for git,for example
git config --global https.proxy 'socks5://127.0.0.1:9999'
竟然有效！