Subvolume overrides not respected

[EnochPrime]

Problem

When creating a config with a subvolume that defines a different targert_preserve_min the volume level definition is used. Might be related to #479.

btrbk command line client, version 0.32.6-dev

Example config

volume /mnt/btrfs
  # local snapshot settings
  snapshot_dir           snapshots
  snapshot_preserve_min  48h
  snapshot_preserve      7d 4w 12m 5y

  # external snapshot settings
  target                 /mnt/btrbackup2
  target_preserve_min    latest

  # data to backup
  subvolume @swarm
    target_preserve_min  all

The above config will attempt to retain only the latest snapshot on the target. If the volume level definition retention is removed then all snapshot will be pushed as expected.