NFS: Don't expose internal READDIR errors to userspace

Fixes a condition whereby the kernel is returning the non-POSIX error
 EBADCOOKIE to userspace.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/dir.c

@@ -565,8 +565,6 @@ static int nfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 		}
 	}
 	unlock_kernel();
-	if (desc->error < 0)
-		return desc->error;
 	if (res < 0)
 		return res;
 	return 0;