Force 2007 XML format

src/main/java/org/gcube/data/transfer/plugins/thredds/ISOMetadataMarshalling.java

@@ -53,7 +53,7 @@ public class ISOMetadataMarshalling {
 	private static MarshallerPool getPool() throws JAXBException {
 		if(pool==null)
 			pool=new MarshallerPool(
-					singletonMap(XML.METADATA_VERSION,"2016"));
+					singletonMap(XML.METADATA_VERSION,"2007"));
 		
 		return pool;
 	}