Update root to v5.30.02

[cjones051073 (Chris Jones)]

Update to the root port

The main changes are :-

• Bump the version to 5.30.02

• remove the option disabling parallel builds, as this is now redundant. Parallel builds work fine, at least for me.

• comment out the kerberos5 variant, which doesn't work. Under discussion with the ROOT team.

• Clean up a bit the way the various pythonXY ports are written. No longer hardcodes the files to copy to the python site-packages during post-destroot, but globs for all files matching *.py*

• Add a python31 variant. No python32 variant yet, since root doesn't yet support this python version.

Chris