[Satellite 6] Upgrade from Red Hat Satellite 6.7 to Satellite 6.8 fails with`ERROR: Tuning option 'checkpoint_segments' found`

Issue

• foreman-maintain upgrade run --target-version 6.8 fails with the below error on Red Hat Satellite 6.

Check if checkpoint_segments configuration exists on the system:      [FAIL]
ERROR: Tuning option 'checkpoint_segments' found.
This option is no longer valid for PostgreSQL 9.5 or newer.
Please remove it from following file and re-run the command.
- /etc/foreman-installer/custom-hiera.yaml
The presence of checkpoint_segments in /etc/foreman-installer/custom-hiera.yaml indicates manual tuning.
Manual tuning can override values provided by the --tuning parameter.
Review /etc/foreman-installer/custom-hiera.yaml for values that are already provided by the built in tuning profiles.
Built in tuning profiles also provide a supported upgrade path.