Python 2.7.3 spec file tested for Centos6.x

I'm not sure if you want CentOS-6-oriented changes here.  If not I'll just use my fork and not issue pull requests from here on out.  There's a README that explains what I'm up to.  Some changes are pure upgrade things, some I think useful tweaks, some just personal preference.  The 'git diff' is obviously useless, because the files are both new, but if you use plain 'diff' to compare with the 2.7.2 spec file, you can see the actual changes.