correctly encode boolean values in openvz configuration

PVE/OpenVZ.pm

@@ -794,7 +794,12 @@ sub create_config_line {
     my $text;
 
     if (defined($data->{value})) {
-	$text .= uc($key) . "=\"$data->{value}\"\n";
+	if ($confdesc->{$key}->{type} eq 'boolean') {
+	    my $txt = $data->{value} ? 'yes' : 'no';
+	    $text .= uc($key) . "=\"$txt\"\n";
+	} else {
+	    $text .= uc($key) . "=\"$data->{value}\"\n";
+	}
     } elsif (defined($data->{bar})) {
 	my $tmp = format_res_bar_lim($key, $data);
 	$text .=  uc($key) . "=\"$tmp\"\n";