Install updated git version on RHEL6

Github doesn't support the version of git that comes with RHEL6. Here are the commands I used to get a supported version installed:

$ sudo rhn-channel --add --channel=rhel-x86_64-server-optional-6
  $ sudo yum install

The annoying part to this was finding the rhn-channel command to enable the optional repo. Most places I looked online wanted me to do this

yum --enablerepo=rhel-6-server-optional-rpms

but my RHEL server wasn't subscribed to that channel for it to be enabled.