guest-overlay: Always recreate squashfs without appending

Without -noappend, we end up with an image containing gast, gast_1, gast_2 etc. after running repeatedly. This way, it is always recreated and contains only what it is supposed to.

guest-overlay/tasks/main.yml

@@ -43,6 +43,7 @@
       - 1000
       - -force-gid
       - 1000
+      - -noappend
   delegate_to: localhost
   run_once: true
   tags: