duplicate code in dir2

[Christoph Hellwig]

On Wed, Jun 22, 2011 at 10:25:43AM -0500, Eric Sandeen wrote:
> Another interesting chunk elsewhere:
> 
> /src/git/linux-2.6/fs/xfs/xfs_da_btree.c(782)
> /src/git/linux-2.6/fs/xfs/xfs_attr_leaf.c(1542)
>                 *action = 0;
>                 return(0);
>         if (count == 0) {

The da_btree code is a big mess with things duplicated all over.
There's a third copy of this in the dir2 code as well.  I have started
consolidating some of this code a while ago in prepation of adding
checksumming to the dir and attr code, but it has bit rotted a bit since
and I've not managed to get back to it.