Lower "bad example" count

-The section, "Use default arguments instead of short circuiting or conditionals"
originally had 2 "bad examples" and 1 "good example."

- This commit lowers the "bad examples" count from 2 -> 1.

  - The 1st "bad example" demonstrated the "conditionals" approach to default values.
  - The 2nd "bad example" demonstrated the "short-circuit" approach to default values.
  - I decided to only show the "short-circuit" approach as the 1 bad example, since that's
    what most people would use traditionally in ES5.
  - Few people actually use the "conditionals" approach, so I felt that warning 
    against the "conditionals" approach was unnecessary.