Bug 26496: Add op field to Budget Planning

Bug 26496: Add op field to Budget Planning

Without this patch, it's impossible to save a budget plan.

With this patch, it is possible to save a budget plan.

Test:
1. Apply patch
2. Modify a budget (e.g. http://localhost:8081/cgi-bin/koha/admin/aqbudgetperiods.pl?op=add_form&budget_period_id=1)
3. Unlock the budget if necessary by unticking "Lock budget" and click "Save"
4. Go to a budget (e.g. http://localhost:8081/cgi-bin/koha/admin/aqbudgets.pl?budget_period_id=1)
5. Click "Planning" and "Plan by libraries"
6. Click "Auto-fill row" on the first line
7. Click "Save"
8. Note that results are saved and shown on the newly loaded page

To verify this patch is necessary, do the test plan without applying the patch.

Signed-off-by: Barbara Johnson <barbara.johnson@bedfordtx.gov>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
(cherry picked from commit fd35df346f73a00b643e675853ba2c8ef321cf66)

Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
(cherry picked from commit 7f4b2f20991fd04da0703fafb7b643a03fcc7e14)

Signed-off-by: Aleisha Amohia <aleishaamohia@hotmail.com>
(cherry picked from commit fc31bc6cee24e07d254155bc5f30a3ad022fa523)
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>