yum命令升级的时候，报出这个错误。
There was a problem importing one of the Python modules required to run yum. The error leading to this problem was: No module named yum Please install a package which provides this module, or verify that the module is installed correctly. It's possible that the above module doesn't match the current version of Python, which is: 2.7.5 (default, Sep 3 2013, 23:16:48) [GCC 4.6.3 20120306 (Red Hat 4.6.3-2)]
解决方法：
sudo vim /usr/bin/yum #修个python所在的路径。比如 #/usr/local/bin/python2.6