[HTTPS-E Rulesets] Cheezburger: update on support subdomain

[Christopher Liu]

To whom it may concern:

I previously mentioned that support.cheezburger.com doesn't have a
matching certificate due to being hosted by Freshdesk.

It turns out that it is possible to rewrite it to
cheezburger.freshdesk.com, but (if I understand correctly) we should
only do that for 4.x. Since there is no Freshdesk ruleset in the 3.x
branch, we should just exclude the domain to avoid issues with mixed
active content.

(Discussion about mixed content elsewhere in Cheezburger will follow
in a separate email.)

C. Liu

P.S. Some other outstanding issues, which I mentioned previously but
may have gotten lost in the shuffle:
- images.cheezburger.com needs to be rewritten to i.chzbgr.com to
avoid a cert error due to EdgeCast (for examples of use, see
www.cheezburger.com/site-directory and jobs.cheezburger.com )
- developer.cheezburger.com has started supporting/enforcing https, so
it shouldn't be excluded/downgraded