报错如下：
bash: git-upload-pack: command not found
fatal: The remote end hung up unexpectedly
原因:原来代码服务器上的git安装路径是/usr/local/git，不是默认路径，根据提示，在git服务器上， 建立链接文件：
解决方法：
# ln -s /usr/local/git/bin/git-upload-pack /usr/bin/git-upload-pack
再次执行 git clone 成功！
报错如下：
bash: git-receive-pack: command not found
fatal: Could not read from remote repository.
# ln -s /usr/local/git/bin/git-receive-pack /usr/bin/git-receive-pack