fix(hosts/btrfs): sort subvolumes before removing

This ensures parents are removed first

Author: Misterio77

hosts/common/optional/ephemeral-btrfs.nix

@@ -19,7 +19,7 @@
         echo "Skipping wipe"
       else
         echo "Cleaning root subvolume"
-        btrfs subvolume list -o "$MNTPOINT/root" | cut -f9 -d ' ' |
+        btrfs subvolume list -o "$MNTPOINT/root" | cut -f9 -d ' ' | sort |
         while read -r subvolume; do
           btrfs subvolume delete "$MNTPOINT/$subvolume"
         done && btrfs subvolume delete "$MNTPOINT/root"