LU-1822 llite: Remove deprecated truncate handler

LU-1822 llite:  Remove deprecated truncate handler

Remove the ll_truncate handler. This handler was only being used
to display a debug message about the truncated object. That line
was moved to a different location, and the handler removed.
This handler is an issue in kernels after 2.6.34 when running the
patchless client. In that version of the kernel the kernel will log a
kernel warning if its called and the inode has a handler for truncate.
The truncate logic was updated some time ago to be more
consistent with the new sequence of events.

Xyratex-bug-id: MRP-597
Reviewed-by: Alexander Zarochentsev <Alexander_Zarochentsev@xyratex.com>
Reviewed-by: Iurii Golovach <iurii_golovach@xyratex.com>
Signed-off-by: Michael McKay <michael_mckay@xyratex.com>
Change-Id: I77b372a2825fd2bdc4b215ee20a979f03dc7d64b
Reviewed-on: http://review.whamcloud.com/3860
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Jinshan Xiong <jinshan.xiong@whamcloud.com>
Reviewed-by: Iurii Golovach <iurii.golovach@gmail.com>