Fix constant names for object status

src/MDObjectStatusSet.php

@@ -11,9 +11,9 @@
  */
 final class MDObjectStatusSet extends MDValueSet {
 
-    const DEFAULT_OBJECT_STATUS_TYPE = 'owned';
+    const DEFAULT_OBJECT_STATUS = 'owned';
 
-    const OBJECT_STATUS_TYPES = [
+    const OBJECT_STATUS = [
         'owned',
         'permanent_loan',
         'borrowed',