Thanks. I still did not try to risk as yum also depends on system python and I am not sure how it works. After all, system-wide updates also done with yum. So I just downloaded the source to my home directory on the smaller SciLinux guinea pig, and README said install is going to go in /usr/local, while system's one resides in /usr/bin and /usr/lib. It also mentioned that RHEL still depends on python 1.7.x, while also uses without problem 2.1 and 2.4. So, after 'configure', 'make', and 'sudo make install' with default options I got everything installed in /usr/local, ensured that in $PATH /usr/local/bin comes before /usr/bin and everything seems fine. Then I made local install of Galaxy and it works just fine. Voila!