Add lab-build snippets and executing them in 'create'. Refactor create/destroy/pristine; also, only virsh destroy VMs if they are 'running'

pristine

@@ -1,10 +1,14 @@
 #!/bin/sh
-
+BUILD=${BUILD:=default}
 LAB=${LAB:=0}
 
 ## Do not touch below this line
 HVN="hvn${LAB}.lab.ipng.ch"
+VMS=$(ls -1 build/${BUILD}/${HVN}/)
 
-## Destroy the VMs and bring them back into pristine state
-echo "*  Restarting VMs from pristine snapshot"
-ssh root@$HVN "set -x; for node in 0 1 2 3; do VM=vpp${LAB}-\${node}; virsh destroy \$VM; zfs rollback ssd-vol0/\${VM}@pristine; done"
+for VM in $VMS; do
+  echo "[$VM] Destroying VM"
+  ssh root@$HVN "/usr/bin/virsh list --all | grep $VM.*running >/dev/null && virsh destroy $VM"
+  echo "[$VM] Rolling VM back to pristine snapshot"
+  ssh root@$HVN "zfs rollback ssd-vol0/${VM}@pristine"
+done