Better check for whether something is an Attribute or not

bootstrap/ramify.alc

@@ -184,7 +184,7 @@ Element function ramify(model : Element):
 			// Primitive values themselves are not copied, so skip that here
 
 			attr_name = read_attribute(model, type_name, "name")
-			if (read_type(model["metamodel"], type_name) == "Attribute"):
+			if (is_nominal_instance(model["metamodel"], type_name, "Attribute")):
 				old_source = reverseKeyLookup(model["model"], read_edge_src(entry))
 
 				if (set_in(copied_attributes, attr_name)):