/etc/modprobe.d is not a file

[Jérôme]

/var/log/syslog tells :
---
cron: (CRON) INFO (Running @reboot jobs)
gpu-manager: /etc/modprobe.d is not a file
gpu-manager: message repeated 4 times: [ /etc/modprobe.d is not a file]
anacron: Normal exit (0 jobs run)
---

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubuntu-drivers-common 1:0.4.17.2
ProcVersionSignature: Ubuntu 4.4.0-62.83-generic 4.4.40
Uname: Linux 4.4.0-62-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.1-0ubuntu2.5
Architecture: amd64
CurrentDesktop: XFCE
Date: Sun Feb 5 20:39:21 2017
InstallationDate: Installed on 2017-02-01 (3 days ago)
InstallationMedia: Xubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
SourcePackage: ubuntu-drivers-common
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.