This directory (and version of CentOS) is depreciated.  For normal users,
you should use /5/ and not /5.10/ in your path. Please see this FAQ
concerning the CentOS release scheme

https://wiki.centos.org/FAQ/General

If you know what you are doing, and absolutely want to remain at the 5.10
level, go to http://vault.centos.org/ for packages. Please keep in mind that 5.10 no longer gets any updates