Based on changes from recent LFSCK, the backup/restore process documentation in the Lustre manual should be updated to include removal of the OI files.

Ideally, the LFSCK process would automatically remove the existing OI files on backup/restore since they are not useful, and this manual step would not be needed. However, given that there are many Lustre releases where the manual step is needed, the documentation should be updated now, and it can later be fixed when the manual process is no longer needed.