On Linux all filesystems are supposed to be operating under Posix'
restricted chown. Restricted chown means it restricts chown to the owner
unless you have CAP_FOWNER.

NOTE: that 2 files outside of fs/xfs have been modified too for this
change.
Reviewed-by: Dave Chinner <david@fromorbit.com>

SGI-PV: 988919

SGI-Modid: xfs-linux-melb:xfs-kern:32413a
Signed-off-by: Tim Shimmin <tes@sgi.com>
Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <david@fromorbit.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>