本次服务器的系统版本是：
CentOS release 6.7 (Final)
解决git clone时报错：The requested URL returned error: 401 Unauthorized while accessing
wget -O git.zip https://github.com/git/git/archive/master.zip
unzip git.zip
cd git-master
autoconf
./configure --prefix=/usr/local
make && make install
mv /usr/bin/git /usr/bin/git_old
ln -s /usr/local/bin/git /usr/bin/git