Bug 21056: Add another flush later

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

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 5abcd3312a)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>

circ/selectbranchprinter.pl

@@ -80,6 +80,7 @@ if ( $branch and my $library = Koha::Libraries->find($branch) ) {
 if ($printer) {
     if (! $userenv_printer or $userenv_printer ne $printer ) {
         $session->param('branchprinter', $printer);         # update sesssion in DB
+        $session->flush();
         $template->param('new_printer', $printer);          # update template
         push @updated, {
             updated_printer => 1,