[rdiff-backup-users] Manually Clean-up Backups

[Damon Timm]

I wasn't paying attention and my target device filled up!

I attempted to run a `--removed-older-than` on the backup in question,
however, I am getting a fatal error:

    Fatal Error: Could not open rdiff-backup directory
    /mnt/backup/daily/home/rdiff-backup-data
    due to
    [Errno 28] No space left on device:
'/mnt/backup/daily/home/rdiff-backup-data/rdiff-backup.tmp.0'

I have tried add the options `--tempdir /tmp --remote-tempdir /tmp`
hoping this might solve the problem but no dice.

I checked the docs but don't see any advice on manually deleting
backups to free up enough space to actually run the
`--remove-older-than option`.

So - my question is: can I safely remove files myself ?  If so, any
recommendations on how to proceed?

Thanks,
Damon