Classification "by-port" should be the last possible effort, *after* having test all the LRU caches. Remove some dead code from `ndpi_detection_giveup()`: `flow->guessed_protocol_id` is never set to any od those voip protocols and at that point in this function we never have both a master *and* a application protocols. Coverage reports (both from unit tests and from fuzzing) confirms that was dead code.