* lib/model: Override scan config for auto-accepted encrypted folders.
Encrypted folders should not have the fs watcher enabled and rarely
benefit from a scheduled rescan. The GUI adjusts the suggested
settings (watcher disabled, one day rescan interval) when accepting a
receive-encrypted folder. Mirror that behavior to the auto-accept
case where the GUI is not involved.
Versioning also does not work well for encrypted folders, same
treatment.