pythonのバージョンをアップデートするとyumが動かなくなるときの対応

■環境

CentOS 5.9
python 2.4.3 -> 2.6.8

■エラー内容

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:
2.6.8 (unknown, Nov 7 2012, 14:47:45)
[GCC 4.1.2 20080704 (Red Hat 4.1.2-52)]

If you cannot solve this problem yourself, please go to
the yum faq at:
http://wiki.linux.duke.edu/YumFaq

■対処方法

emacs /usr/bin/yum
上記のファイルの先頭部分を変更

#!/usr/bin/python
↓
#!/usr/bin/python2.4

明示的に2.4のバージョンのpythonを使うように変更しましょう