Reduce size of Kaldi server snapshot

[afred]

description: to get though the installation, we bumped the root volume to 65G. Turns out 16G will do. So we need to downsize, but in order to do that, you have to either:

1. rsync data from the big instance to the smaller one... OR.
2. Just re-do the setup, using our setup instructions, only with a smaller root volume.

done when: we have a "golden image" snapshot of an instance that has a working Kaldi installation on a 16G root volume.