Bug 9046: FIX wrong test on an arrayref instead of an array

EmbedItemsInMarcBiblio does not embed items when the itemnumbers param
is given. That breaks the export tools (used from commandline).

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>

C4/Biblio.pm

@@ -2851,6 +2851,7 @@ sub EmbedItemsInMarcBiblio {
     my @item_fields;
     my ( $itemtag, $itemsubfield ) = GetMarcFromKohaField( "items.itemnumber", $frameworkcode );
     while (my ($itemnumber) = $sth->fetchrow_array) {
+        next if @$itemnumbers and not grep { $_ == $itemnumber } @$itemnumbers;
         require C4::Items;
         my $item_marc = C4::Items::GetMarcItem($biblionumber, $itemnumber);
         push @item_fields, $item_marc->field($itemtag);