How do CS graduate school admissions weigh an unrelated master?
If your final goal is to have a CS Ph.D., getting a masters in sociology first will in no way help you reach that goal.  Doing option II may be viewed as a "waste of time" by CS admissions committees, though it probably won't preclude you from getting into a masters program afterwards.  I'm guessing the net effect will be slightly negative from the point of view of a CS admissions committee.

However, it doesn't mean you shouldn't do option II, especially if you think you'll enjoy it.  You might even find your career plans changing after getting a masters in sociology.