Actually this is very good question.
Now in the JDBC case, the JCA connector or data source is already defined by the Container. So there is no need to define "connector-jdbc", however you will see a module "translator-jdbc". When the container does not provide a connector, Teiid is provides that with its own connector to access that resource.
I will have a blog or WIKI article on this soon. The previous blogs "JCA Container Integration, Why Teiid needs it?" give you more back ground on 7.0 changes and why.