This uses the v3 json as a source for the first time. The test needed
some updating because Google removed a couple more logs - in the future
this should hopefully not be neccessary anymore because I think v3
should retain all logs.
In theory this might be neat in 5.1.
This commit switches to only allowing the CT logs that are currently
accepted by Google Chrome - which makes much more sense for us since
this is (potentially) used for validation.
Additional CT logs can be added in user-scripts.