OracleGeoResource keeps its own IService

The OracleGeoResource defines a
OracleServiceImpl parent;

It should actually use (from the superclass IGeoResource):

protected IService service = null;

uDig is failing to add oracle layers, because IGeoResource.service(IProgressMonitor ) : IService is returning null for the OracleGeoResource.

The fix is to remove OracleServiceImpl's parent and use super.service.