Guest and network configuration is setup using the libvirt
virtualization API. The [start|stop]_testing scripts have been updated
accordingly.
qemu/KVM does not currently support a hostfs, so the shared build tree
mount has been dropped for now.
Reduce the coupling of the different scripts.
make-testing : Build the testing environment
start-testing : Start switches and guests
do-tests : Run tests
stop-testing : Stop switches and guests