Update FrameworkSynchronizer to avoid the "Object not yet known to Isis" exception

Sometimes the Isis synchronizer has not yet picked up the domain entity and needs to be created.

It has been detected when using the @Persistent ("dependentElement="true") JDO annotation, such as in:

@PersistenceCapable
@Inheritance(strategy = InheritanceStrategy.NEW_TABLE)
public class TimeScale extends AbstractScale {

// {{ TimeScaleLevels (Collection)
@Persistent(mappedBy = "timeScale", dependentElement = "true")
private SortedSet<PointInTime> timeScaleLevels = new TreeSet<PointInTime>();

...
}

The solution is simply to update the ensureRootObject method.
Replace the "getAdapterManager().getAdapterFor(pojo)" by "getAdapterManager().adapterFor(pojo)" as it will create the adapter if it's still not available to Isis.