[XFS] Use xfs_idestroy() to cleanup an inode.

SGI-PV: 981498

SGI-Modid: xfs-linux-melb:xfs-kern:31927a

Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
Signed-off-by: David Chinner <david@fromorbit.com>