Bug 16328: follow-up for bug 15044 - Fix datatable error

Bug 16328: follow-up for bug 15044 - Fix datatable error

Bug 15044 added a new column to the suggestion table at the OPAC but
forgot to modify the DT params.

Test plan:
The suggestion table at the OPAC should not be broken with this patch.

NOTE: Sorting was broken prior to patch.
      Sorting was fixed after patch.
      The added null causes the field count to match up properly.

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Brendan Gallagher <brendan@bywatersolutions.com>