Fix broken links to the new VM image guide.

Fix bug 1185919

Cherry pick from https://review.openstack.org/#/c/31112/.

Change-Id: Ib926592bf523945d7d12fa8b45d7a6ce17fe7dd1
Fix typo: Deepian -> Debian

Change-Id: I5d90661a39a75192ebda52e3bb6a51b510b58866