Bug 36577: (bug 34478 follow-up) marc21_linking_section.pl not working

Bug 36577: (bug 34478 follow-up) marc21_linking_section.pl not working

After applying "Bug 34478: op =~ ^cud- everywhere" the plugin
marc21_linking_section.pl stopped working properly.  Since the plugin
does not perform a CUD operation, the GET request can be used, and so
the use of CSRF token is not needed.

The patch fixes also problems with result page numbers display.

Test plan
=========
1. Configure a MARC bibliographic framework to use the plugin
   marc21_linking_section.pl (e.g. in 773 $t).
2. Start creating a new record and go to 773 $t. Activate the plugin to find
   the any record to become the host record (perform a search for any
   common word, like 'and').
3. You will get no results.
4. Apply the patch, restart plack etc.
5. Repeat p. 2 - you should now see some results, possibly more than one
   page.  You should be able to change page with Next/Previous arrows and
   also with the page numbers.

BTW, QA people - maybe it would pay to remove the commented code present there
since the very beginning (2012).

Signed-off-by: Roman Dolny <roman.dolny@jezuici.pl>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>