[COOK-3555] Rename example configuration to listen_addresses

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
[COOK-3490] Fix pg gem install for v9.2 on RHEL 6
[COOK-2383] Use postgresql 9.0 on Amazon Linux

Signed-off-by: Seth Vargo <sethvargo@gmail.com>
[COOK-3553] Remove apt-get update

Signed-off-by: Seth Vargo <sethvargo@gmail.com>