Fixing bug disabling JSON inline serialization for non managed types

Hi,

In previous versions, I used to annotate some JPA repositories with exported=false in order to avoid Link creation in an entity. In such case, these entities was just serialized through standard JSON serialization like { "property":"value"}

The following patch is bypassing an optimization which is actually breaking this comportment.

Thanks a lot for your amazing work done so far !

Romain