JeOS 19: Add qemu-guest-agent

It was argued that the agent is closely related to
virtualization testing, and it is small enough to
justify inclusion.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
Merge pull request #1224 from autotest/jeos-19-update

JeOS 19: Add qemu-guest-agent