Bug 10049 [Alternate] Comments tab shows ( ) instead of ( 0 ) on translated templates

This patch is an alternate solution to the problem of "0" not appearing
on the comment tab in translated templates. It uses the Template Toolkit
option of specifying a default value for a variable:

[% reviews.size || 0 %]

This syntax is already in use elsewhere in the template.

Same test plan:

1) Make sure comments/reviews are activated
2) Find a record with 0 comments/reviews in the opac
3) The tab shows: Comments ( 0 )
4) Switch to any other languages.
5) Tab now shows: <translation of Comments> ( )
6) Apply patch
7) Check English templates stil work correctly
8) Rerun 'perl translate install <langcode>
9) Check display is now correct.
10) Also check that number shows correctly for records
    with comments.

Signed-off-by: Magnus Enger <magnus@enger.priv.no>
Tested with nb-NO. English still works after the patch. Norwegian
was showing "Comments" untranslated, which had me a bit unnerved.
Turns out the string to be translated changed from "Comments ( %s%s%s%s )"
to "Comments ( %s )", so to make sure all was well, I had to update
the nb-NO translation, fix the number of %s's in the Norwegian string,
make sure it was not marked as fuzzy and then install nb-NO. And it
works!

Signed-off-by: Jonathan Druart <jonathan.druart@biblibre.com>
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>

koha-tmpl/opac-tmpl/prog/en/modules/opac-detail.tt

@@ -946,7 +946,7 @@ YAHOO.util.Event.onContentReady("furtherm", function () {
     </li>
 [% END %]
 [% IF ( reviewson ) %]
-    <li id="tab_comments"><a href="#comments">Comments ( [% IF reviews.defined %][% reviews.size %][% ELSE %]0[% END %] )</a></li>
+    <li id="tab_comments"><a href="#comments">Comments ( [% reviews.size || 0 %] )</a></li>
 [% END %]
 
 [% IF ( NovelistSelectProfile ) %]