avoid an error message in mp chat when we run headlessly

src/display_chat_manager.cpp

@@ -98,7 +98,7 @@ void display_chat_manager::add_chat_message(const time_t& time, const std::strin
 	try {
 		// We've had a joker who send an invalid utf-8 message to crash clients
 		// so now catch the exception and ignore the message.
-		msg = font::word_wrap_text(msg,font::SIZE_SMALL,my_disp_.map_outside_area().w*3/4);
+		msg = my_disp_.video().faked() ? "" : font::word_wrap_text(msg,font::SIZE_SMALL,my_disp_.map_outside_area().w*3/4);
 	} catch (utf8::invalid_utf8_exception&) {
 		ERR_NG << "Invalid utf-8 found, chat message is ignored." << std::endl;
 		return;