Trivial: Fix the comment of TempestConfigPrivate

During the review of I98e75ed52f754a45d0774067fd1713bee2cecb64
I was confused due to this original comment because that is a
class and it is impossible to use a class from the same class.
This patch fixes the comment.

Change-Id: Ib14e53f3824d03154c65cf0106b5c2e1f2df13d5
1 file changed