[SCSI] Redundant this_count check in sd_init_command()

I was going over the scsi I/O submit path, when sd_init_command
construct the scsi command, this_count is already checked in the
previous else if clause.  Why does it need to check it again in
the last else block?

Patch to delete the spurious check.

Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>