bug#26353: GuixSD /tmp cleaner fails to clean when Umlauts like "ä" are used in filenames

[Ludovic Courtès]

Hello!

Finally fixed with commit 76c321d8e85683091ecbcd3afe8c56fb7c45c00a.
I opted for a simpler approach (and I wonder why it didn’t come to mind
earlier than this…).

Thanks for your patience, and bye bye immortal files!  :-)

Ludo’.