extent-tree.h uses btrfs_delayed_ref_head in a function argument but
doesn't pull it's declaration from anywhere, add it to the top of the
header.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>