Bug 25890: Update sorting column for checkouts table

Test plan:
- Check some items out, all from different libraries
- Modify the checkout and due dates, like:
    2018-10-22
    2018-01-23
    2018-05-27
- Sort by checkout date, verify it is actually sorting on homebranch
- Apply patch
- Reload page
- Note you can now sort items correctly

Signed-off-by: Owen Leonard <oleonard@myacpl.org>

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

koha-tmpl/intranet-tmpl/prog/js/checkouts.js

@@ -377,7 +377,7 @@ $(document).ready(function() {
                     "bVisible": false,
                 },
                 {
-                    "iDataSort": 9, // Sort on hidden unformatted issuedate column
+                    "iDataSort": 10, // Sort on hidden unformatted issuedate column
                     "mDataProp": "issuedate_formatted",
                 },
                 {