rescanning due to browse operations

[darrell-k]

At some stage we should look at the processing below Slim::Schema::find because it's not working completely correctly.

See https://forums.lyrion.org/forum/user-forums/logitech-media-server/1796451-rescanning-using-a-sqlite-table-as-reference-instead-of-referring-file-system?p=1797348#post1797348 for an example.

Needs full analysis, but just creating this issue for now so hopefully it's not forgotten.