mhwd not uninstalling properly nvidia drivers

[joshirio]

Similar to issue #37, mhwd is not removing the nvidia proprietary driver properly.
Maybe a similar solution to manjaro/mhwd-db#9 could solve this.

After removing the proprietary driver (testet with video-nvidia-340xx) mhwd should restore nouveau if installed (usually yes, because the driver is not conflicting as a package).
Instead, nvidia module is still getting loaded, causing errors on boot, since modules are no longer installed:

cat /etc/modules-load.d/mhwd-gpu.conf
##
## Generated by mhwd - Manjaro Hardware Detection
##

nvidia

Dsiplay manager fails to start because nouveau remains blacklisted, even after removing nvidia with mhwd:

[root@manjaro /]# cat /etc/modprobe.d/mhwd-gpu.conf
##
## Generated by mhwd - Manjaro Hardware Detection
##
blacklist nouveau
blacklist ttm
blacklist drm_kms_helper
blacklist drm

Forum thread here.

In case of sddm, it's not possible to login to TTY because it keeps trying to spawn a new instance but fails, the only solution to fix a machine in this state is to boot with live media and use chroot to manually edit the files from above...

EDIT: just to add another general manjaro-settings mhwd issue: when installing a driver or removing one it is not possible to reboot/shutdown/log out from the menu (tested on KDE), only through command line makes this possible. So a simple "Do you want to restart now?" prompt after installing a driver with manjaro-settings would help users who don't know how to restart the system.