Expect script to configure a clean install of vyos for sending to amazon.
Just wait for vyos login prompt on install too, so to not interfere with grub prompts at all.
Fix bug with expecting vyos prompt when we're going to get a root prompt.

Also add comment above bit about ttyS0 to remember to remove this later.
VirtualBox build procedure: it works!

Added the remaining steps - ejecting the CD drive, booting back up, and running the configure script.