fix non hydrated EagerCursor.

Map hydrate properties of EagerCursor to the same properties of its BaseCursor.
I was trying to speed some queries with this combination:
$qb = $this->doctrine->createQueryBuilder('collection_name')
->eagerCursor(true)
->hydrate(false);

It didn't work because the EagerCursor lost information about the hydration flag on its way.
This PR fixes this problem.