btrfs/287,btrfs/293: filter all btrfs subvolume delete calls

btrfs/287,btrfs/293: filter all btrfs subvolume delete calls

Some of our btrfs subvolume delete calls get put into the golden output,
and many of them simply _filter_scratch.  This works fine, but we
recently changed btrfs subvolume delete output, and it would have been
nice to simply filter this in one place.  We have a
_filter_btrfs_subvol_delete helper, but it's only used in one place.
Fix all of these uses to call _filter_btrfs_subvol_delete, this will
allow for follow up fixes against _filter_btrfs_subvol_delete itself to
deal with changed output.

Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>