Update README

I upgraded the version of Ubuntu (13.04 to 13.10) on my AWS instance on
Jan 4th. This also updated Apache from (I presume 2.2) to 2.4. Apache
2.4 has changed something to do with permissions[1] so I've had to
change the apache config. I got this config update from the Puppet
config file for Passenger[2].

[1] http://httpd.apache.org/docs/2.4/upgrading.html
[2] http://docs.puppetlabs.com/guides/passenger.html