Test our vagrant-libvirt -based build system with Jessie's Vagrant

Originally created by @intrigeri on #8086 (Redmine)

Vagrant 1.6.5+dfsg1-1 got uploaded to Debian, and will likely be part of Jessie. As long as our main “easy” build system is using Vagrant, we should try to support that version.

Feature Branch: feature/6354-vagrant-libvirt

Parent Task: #6354 (closed)

Edited May 15, 2020 by intrigeri

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information