There are certain movies that should never get a sequel, regardless of how beloved the film is or how well it did at the box office. This declaration can be a tough proposal, because selfishly I want some stories to continue, however convoluted and stretched they might become. On the flip side, I also know that my selfishness can lead to crappy sequels and the pollution and tainting of the original. That’s why my feelings about “The Descent 2” are …