Bug 15711: Follow up batch_id not used

Bug 15711: Follow up batch_id not used

Changed batch_id to image_id in the template, as the multiparam
would catch the array case.

TEST PLAN
---------
1) attempt to delete a selected item, but get a warning.
2) apply this follow up
3) attempt to delete a selected item, it deletes.
4) run koha qa test tools

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Mason James <mtj@kohaaloha.com>