Fix public key URL

Github recently started serving raw content from a different domain, so this cURL command no longer works. The old domain redirects to the new domain, but because cURL was not invoked with the -L flag, it does not follow the redirect.

The URL has been updated to the new address.
Merge remote-tracking branch 'origin/patch-1'

* origin/patch-1:
  Fix public key URL
Change the locale/timezone/etc to Australia
Install python + postgres, not ruby + chef

Also install the guest additions from within the guest, not by mounting
an iso from the host.