"Administer CAPTCHA settings" ignored if "Skip CAPTCHA" is not also set

Granted, it's not a common setup -- allowing someone to administer the settings but not skip the CAPTCHA -- but I ran into it when setting up CAPTCHAs on node-add forms. I was being too lazy to switch to another browser and log in as another user. :)

Anyhow, this setup streamlines administering CAPTCHAs on forms as you have both the CAPTCHA and the admin links right there.

The attached patch allows the CAPTCHA admin fieldset to show regardless of the user's "Skip CAPTCHA" permissions. It also tweaks the admin fieldset to use a different $form key so that you can see both the CAPTCHA and admin options.