Bug 29416: (bug 28941 follow-up) Restore suggestion prefill

From commit 586bed1319
     Bug 28941: Filter suggestion inputs at the OPAC

But later in the script we send { suggestion => %$suggestion } to the
template and so erase the variable previously passed.

Test plan:
Login at the OPAC
Go to the bibliographic detail page
Suggest for purchase
=> The form must be prefilled!

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>

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

opac/opac-suggestions.pl

@@ -254,7 +254,7 @@ my @mandatoryfields;
     }
     if ( $biblionumber ) {
         my $biblio = Koha::Biblios->find($biblionumber);
-        $template->param(
+        $suggestion = {
             biblionumber    => $biblio->biblionumber,
             title           => $biblio->title,
             author          => $biblio->author,
@@ -263,7 +263,7 @@ my @mandatoryfields;
             publishercode   => $biblio->biblioitem->publishercode,
             collectiontitle => $biblio->biblioitem->collectiontitle,
             place           => $biblio->biblioitem->place,
-        );
+        };
     }
 }