LU-1714 lnet: Properly initialize sg_magic value

LU-1714 lnet: Properly initialize sg_magic value

When the CONFIG_DEBUG_SG flag is enabled in the kernel, we must ensure
the sg_magic field is properly initialized. Otherwise, internal kernel
assertions will fail when trying to verify this field. As a result,
certain calls to sg_* function had to be changed or inserted to ensure
the sg_init_table function would be called, initializing the magic
value. Also, we need to ensure this value isn't zeroed out in the
kiblnd_setup_rd_kiov function.

Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Alexander Boyko <alexander_boyko@xyratex.com>
Reviewed-by: Alexander Zarochentsev <alexander_zarochentsev@xyratex.com>
Reviewed-by: Andrew Perepechko <andrew_perepechko@xyratex.com>
Change-Id: I5b6b265a4a8dd37408bb78decd79ed54e0f9251b
Reviewed-on: http://review.whamcloud.com/3709
Tested-by: Hudson
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>