'nightly' repo dist from apt-mk is broken, so switch to '2017.12'.
Change-Id: Ie12dfc2a499910b8b98a63886ba16044e66435f5
Signed-off-by: Alexandru Avadanii <Alexandru.Avadanii@enea.com>
   export DEBIAN_FRONTEND=noninteractive
   OLD_DOMAIN=\$(grep -Pzo "id: cfg01\.\K(\S*)" /etc/salt/minion.d/minion.conf) || true
   BOOTSTRAP_SALTSTACK_OPTS=" -r -dX stable 2016.11 " \
-    MASTER_HOSTNAME=cfg01.${CLUSTER_DOMAIN} DISTRIB_REVISION=nightly \
+    MASTER_HOSTNAME=cfg01.${CLUSTER_DOMAIN} DISTRIB_REVISION=2017.12 \
       EXTRA_FORMULAS="nfs" \
         ./salt-master-init.sh
   salt-key -Ay