Run VM-sync only when server is reachable.

roles/lmn_vm/files/vm-run

@@ -231,8 +231,11 @@ export XDG_CONFIG_HOME="/tmp/${UID}/.config"
 
 if  ! virsh --connect="${QEMU}" list | grep "${VM_NAME}-clone"; then
     echo "VM not yet running."
-    sudo /usr/local/bin/desktop-sync
-    check_images
+    # only when school-network is reachable
+    if nslookup "${SEEDBOX_HOST}"; then
+      sudo /usr/local/bin/desktop-sync
+      check_images
+    fi
     if [[ "${NEWCLONE}" = 1 ]] || [[ ! -f "${VM_DIR}/${VM_NAME}-clone.qcow2" ]]; then
         create_clone "${VM_NAME}"
     fi