d/postinst: configure removes models

debian/dspawn.postinst

@@ -23,6 +23,11 @@ case "$1" in
         deb-systemd-invoke enable systemd-networkd.service
         deb-systemd-invoke enable machines.target
         deb-systemd-invoke start systemd-networkd.service
+
+        for m in .jessie .stretch .buster .stable .testing .unstable
+        do
+            find /var/lib/machines -maxdepth 1 -type d -name ${m}* -exec rm -r {} \;
+        done
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)