libxfs: remove i_transp

libxfs: remove i_transp

i_transp was removed from kernel code back in 2011, but it was left
in userspace.  It's only used in a few asserts in transaction code
(as it was in the kernel) so there doesnt' seem to be a compelling
reason to carry it around anymore.

Source kernel commit: f3ca87389dbff0a3dc1a7cb2fa7c62e25421c66c

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>