Remove old migrations from RAUC hook (#4083)

As we're moving to another major release and 15.2 will be mandated update
before 16.0, we can (or even must) remove some old migrations.

buildroot-external/rootfs-overlay/usr/libexec/raucdb-update

@@ -3,11 +3,6 @@
 
 set -e
 
-# Remove rauc.db from old location before migration in HAOS 15.
-if [ -f /mnt/data/rauc.db ]; then
-    rm -f /mnt/data/rauc.db
-fi
-
 if grep -q 'slot\.boot\.0' /mnt/boot/rauc.db; then
     echo "[INFO] rauc.db already contains slot information"
     exit 0