Use specified port when testing SMTP conf

When saving the configuration in the manager, the SMTP test would fail
if your SMTP server is not on the standard port 25

The test now takes the port into account

lemonldap-ng-manager/lib/Lemonldap/NG/Manager/Conf/Tests.pm

@@ -325,7 +325,11 @@ sub tests {
               if ($@);
 
             # Create SMTP object
-            my $smtp = Net::SMTP->new( $conf->{SMTPServer}, Timeout => 5 );
+            my $smtp = Net::SMTP->new(
+                $conf->{SMTPServer},
+                Timeout => 5,
+                ( $conf->{SMTPPort} ? ( Port => $conf->{SMTPPort} ) : () ),
+            );
             return ( 1,
                 "SMTP connection to " . $conf->{SMTPServer} . " failed" )
               unless ($smtp);