Update to Drupal 8.2.0. For more information, see https://www.drupal.org/project/drupal/releases/8.2.0

core/modules/rdf/rdf.module

@@ -70,7 +70,7 @@ function rdf_help($route_name, RouteMatchInterface $route_match) {
  */
 function rdf_get_mapping($entity_type, $bundle) {
   // Try loading the mapping from configuration.
-  $mapping = entity_load('rdf_mapping', $entity_type . '.' . $bundle);
+  $mapping = RdfMapping::load($entity_type . '.' . $bundle);
 
   // If not found, create a fresh mapping object.
   if (!$mapping) {

core/modules/rdf/tests/src/Kernel/Field/FieldRdfaTestBase.php

@@ -167,7 +167,7 @@ abstract class FieldRdfaTestBase extends FieldKernelTestBase {
    * @param array $arguments
    *   Some arguments for the xpath.
    *
-   * @return array|FALSE
+   * @return array|false
    *   The return value of the xpath search. For details on the xpath string
    *   format and return values see the SimpleXML documentation,
    *   http://php.net/manual/function.simplexml-element-xpath.php.