Export compile directory to guests

Use 9p over virtio to share files on the host with the guest domains.
The files are accessible in the guests /hostfs directory.

testing/stop-testing

@@ -6,6 +6,7 @@ echo "Stopping test environment"
 
 NETWORKS="vnet1 vnet2 vnet3"
 KNLTARGET=/var/run/kvm-swan-kernel
+HOSTFSTARGET=/var/run/kvm-swan-hostfs
 
 [ `id -u` -eq 0 ] || die "You must be root to run $0"
 
@@ -26,3 +27,6 @@ done
 
 log_action "Removing kernel $KERNEL"
 execute "rm $KNLTARGET"
+
+log_action "Removing link to hostfs"
+execute "rm $HOSTFSTARGET"