Add LAC swapping for osmo-msc

Make LAC config availble to the shell.
Run a script on MSC restart to change the lac and write a state flag to disk.

Due to the fact that osmo-msc may restart due to crash or power outage
hence loosing all VLR state, force all UE to send a LUR by changing the LAC
on all BTS via CTRL commands to osmo-bsc.

modules/rhizo_base/files/bin/swap_lac.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+
+. /home/rhizomatica/bin/vars.sh
+
+_ALT_LAC=""
+if [ -f /etc/osmocom/alt_lac ]; then
+	_ALT_LAC=$(cat /etc/osmocom/alt_lac)
+fi
+
+if [ "$_ALT_LAC" == "" ]; then
+	_ALT_LAC=1
+else
+	_ALT_LAC=""
+fi
+echo $_ALT_LAC > /etc/osmocom/alt_lac
+/bin/sync
+for bts in "${!BTS[@]}" ; do
+	echo "BTS $bts:"
+	/usr/bin/osmo_ctrl.py -d 127.0.0.1 -p 4249 -s bts.$bts.location-area-code $_ALT_LAC${LAC[$bts]}
+	/usr/bin/osmo_ctrl.py -d 0 -p 4249 -s bts.$bts.send-new-system-informations 1
+done

modules/rhizo_base/files/systemd/osmo-msc.override

@@ -1,3 +1,4 @@
 [Service]
 ExecStart=
 ExecStart=/usr/bin/osmo-msc -c /etc/osmocom/osmo-msc.cfg -l /var/lib/osmocom/sms.db
+ExecStartPost=/home/rhizomatica/bin/swap_lac.sh