Description of problem:

After disabling the modular repos ( https://bugzilla.redhat.com/show_bug.cgi?id=1656509 ), dnf system-upgrade manages to upgrade to f30, but does not reboot at the end of the upgrade process.


Version-Release number of selected component (if applicable):
python3-dnf-plugin-system-upgrade-4.0.2-1.fc{29,30}


How reproducible:
Seemingly always?


Steps to Reproduce:
1. rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-30-primary
2. dnf -y system-upgrade download --refresh --releasever=30 --allowerasing
3. dnf -y system-upgrade reboot

This is my %post:

%post

for repo in fedora-modular updates-modular f29
do dnf config-manager --set-disabled $repo
done

dnf -y install dnf-plugin-system-upgrade
dnf -y update --exclude=kernel*

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-30-primary
dnf -y system-upgrade download --refresh --releasever=30 --allowerasing
dnf -y system-upgrade reboot

%end


Actual results:
Upgrade happens, but the system sits forever at the "Upgrade complete! Cleaning up and Rebooting..." stage.
Systemd says  "reached target Offline System Update"


Expected results:
Rebooting at the end of upgrade


Additional info:
Sending CTRL+ALT+DEL is enough to reboot the system properly into f30.