Thanks for the report.
I've added this for the next upload:
> -----Original Message-----
> From: Christoph Anton Mitterer [mailto:cales...@scientia.net]
> Sent: Saturday, February 10, 2018 11:28 AM
> To: Debian Bug Tracking System <sub...@bugs.debian.org>
> Subject: Bug#890064: smbios-utils: properly clean up legacy config files
> Package: smbios-utils
> Version: 2.4.0-1
> Severity: normal
> Apparently the package smbios-utils used to contain:
> but no longer does.
> Therefore, the following happens on upgrade:
> Unpacking smbios-utils (2.4.0-1) over (2.3.1-2) ...
> dpkg: warning: unable to delete old directory '/etc/yum/pluginconf.d':
> not empty
> dpkg: warning: unable to delete old directory '/etc/yum': Directory not empty
> Please remove the obsolete config file on one of the next upgrades with the
> maintainer script helpers.