Bug 41764: ISSN hidden input missing from Z39.50 search form navigation

This patch modifies the Acquisitions and Cataloging Z39.50 search forms
so that the pagination form includes a hidden ISSN input. This is
necessary for the form to submit the same search parameters each time
the user requests a new page of results.

To test, apply the patch and go to Acquisitions.

- Search for a vendor, and create a basket if necessary.
- Add to the basket and choose "From an external source."
- In the "ISSN" field, enter a partial ISSN number, e.g. 0361, and
  search.
- At the bottom of the search results, click the "Next page" button.
- The second page of results should load correctly. At the top of the
  table of results it should say "You searched for: ISSN: 0361"
- Perform the same test in Cataloging:
  - Cataloging -> New from Z39.50/SRU

Sponsored-by: Athens County Public Libraries
Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Andrew Fuerste Henry <andrew@bywatersolutions.com>
Signed-off-by: Laura Escamilla <laura.escamilla@bywatersolutions.com>

koha-tmpl/intranet-tmpl/prog/en/modules/acqui/z3950_search.tt

@@ -276,6 +276,7 @@
                         <input type="hidden" name="current_page" id="current_page" value="[% current_page | html %]" />
                         <input type="hidden" id="searchtitle" name="title" value="[% title | html %]" />
                         <input type="hidden" id="isbn" name="isbn" value="[% isbn | html %]" />
+                        <input type="hidden" id="issn" name="issn" value="[% issn | html %]" />
                         <input type="hidden" id="lccall" name="lccall" value="[% lccall | html %]" />
                         <input type="hidden" id="author" name="author" value="[% author | html %]" />
                         <input type="hidden" id="publicationyear" name="publicationyear" value="[% publicationyear | html %]" />

koha-tmpl/intranet-tmpl/prog/en/modules/cataloguing/z3950_search.tt

@@ -221,6 +221,7 @@
                             <input type="hidden" name="current_page" id="current_page" value="[% current_page | html %]" />
                             <input type="hidden" id="title" name="title" value="[% title | html %]" />
                             <input type="hidden" id="isbn" name="isbn" value="[% isbn | html %]" />
+                            <input type="hidden" id="issn" name="issn" value="[% issn | html %]" />
                             <input type="hidden" id="lccall" name="lccall" value="[% lccall | html %]" />
                             <input type="hidden" id="controlnumber" name="controlnumber" value="[% controlnumber | html %]" />
                             <input type="hidden" id="srchany" name="srchany" value="[% srchany | html %]" />