TT#12206 Set custom boot option "net.ifnames=0" in GRUB in Vagrant boxes

We need to disable consistent network device naming to get our
"eth0" back, otherwise we have "random" interface names (which
are stable across reboots in the same environment, but aren't
really predictable by their names).

See
https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/
for more information.

Until we've full support for the new interface names let's
disable this feature in our Vagrant environments.

Change-Id: I0f141e585456d64ee7eba7b7e78af938be26bfc2

deployment.sh

@@ -262,6 +262,19 @@ install_vbox_iso() {
   echo "${vbox_checksum} ${vbox_isofile}" | sha256sum --check || die "Error: failed to compute checksum for Virtualbox ISO. Exiting."
 }
 
+set_custom_grub_boot_options() {
+  echo "Adjusting default GRUB boot options (enabling net.ifnames=0)"
+  sed -ie 's/^GRUB_CMDLINE_LINUX_DEFAULT="\(.*\)"/GRUB_CMDLINE_LINUX_DEFAULT="\1 net.ifnames=0"/' "${TARGET}/etc/default/grub"
+
+  echo "Invoking update-grub"
+  grml-chroot $TARGET update-grub
+
+  if [ -d "${TARGET}/etc/.git" ]; then
+    echo "Commit /etc/default/grub changes using etckeeper"
+    chroot "$TARGET" etckeeper commit "/etc/default/grub changes"
+  fi
+}
+
 ensure_augtool_present() {
   if [ -x /usr/bin/augtool ] ; then
     echo "/usr/bin/augtool is present, nothing to do"
@@ -1774,6 +1787,12 @@ EOT
 
 fi
 
+case "$DEBIAN_RELEASE" in
+  stretch)
+    set_custom_grub_boot_options
+    ;;
+esac
+
 if "$CARRIER_EDITION" ; then
   echo "Nothing to do on Carrier, /etc/network/interfaces was already set up."
 elif ! "$NGCP_INSTALLER" ; then