Bug 18692 - When SMS is enabled the OPAC messaging table is misaligned

Bug 18692 - When SMS is enabled the OPAC messaging table is misaligned

Bug 6726 had corrected the fact that when SMS is enabled the messaging table is missing a column.
Bug 6458 has broken this.
The SMS column is missing an else case with cell containing only "-" like other columns.

Test plan :
- set SMSSendDriver preference empty
- go to OPAC patron messaging
- column SMS should not be visible
- set SMSSendDriver preference not empty
- go to OPAC patron messaging
- column SMS appears with checkboxes

Signed-off-by: Michael Andrew Cabus <michael@bywatersolutons.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>