Refactor the things that are common between bird and frr build types -- no-op for the build/ output

build/bird/hvn1.lab.ipng.ch/vpp1-1/root/lab-build/disable-frr

@@ -0,0 +1,7 @@
+#!/bin/sh
+
+echo " * Disabling FRR"
+for i in frr; do
+  rm -f /etc/systemd/system/multi-user.target.wants/${i}.service
+  ln -sf /dev/null /etc/systemd/system/${i}.service
+done