DefaultIOService: skip event when nothing saved

If no saver was found, we should not broadcast a DataSavedEvent. Doing
so is inconsistent with the open method, which only publishes a
DataOpenedEvent when non-null data was actually opened successfully.

Author: ctrueden

src/main/java/org/scijava/io/DefaultIOService.java

@@ -99,8 +99,8 @@ public void save(final Object data, final String destination)
 		final IOPlugin<Object> saver = getSaver(data, destination);
 		if (saver != null) {
 			saver.save(data, destination);
+			eventService.publish(new DataSavedEvent(destination, data));
 		}
-		eventService.publish(new DataSavedEvent(destination, data));
 	}
 
 	// -- HandlerService methods --