Bug 13423: Remove unused JS function in serials-edit.tt

Bug 13423: Remove unused JS function in serials-edit.tt

This patch removes unused code:
 * barcode_check() function, with untranslatable strings
 * commented call to this function

To test:
1. Apply the patch
2. Check serials receive, no changes shall be detected

NOTE: I did not run this test plan.

Verification steps
------------------
1. Find out where barcode_check is used.
   $ git grep barcode_check
   -- This is only in serials-edit.tt and serials-receive.tt
2. This patch only affects serials-edit.tt, so
   check who put the <!--onsubmit="return barcode_check()">-->
   $ git blame -L130 koha-tmpl/intranet-tmpl/prog/en/modules/serials/serials-edit.tt
   -- note the commit related number.
3. Check out the commit.
   $ git show 77b64098
   -- should show bug 5917, but the patches on bugzilla don't
      have the change nicely, so...
4. Hunt through the pages to find the change.
   -- Note: it is part of a "new file" diff!
5. Since this code hasn't been running since it was added...
6. apply the patch
7. run koha-qa test tools

Signed-off-by: Mark Tompsett <mtompset@hotmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>