This allows passing a SSL cert and key to a load balancer to use SSL.
If a certificate is present, the expiry time and certificate subject are
available.
Brightbox is now moving to using the default Ubuntu Cloud Images
(http://cloud-images.ubuntu.com/) where we are also using the naming
convention used there.
So the image selector has been updated to select the latest version of
Ubuntu (i386, official Brightbox) image if no image is specified with
the new format.