Index: src/wp-includes/session.php
===================================================================
--- src/wp-includes/session.php	(revision 29221)
+++ src/wp-includes/session.php	(working copy)
@@ -181,7 +181,7 @@
 	 */
 	final public static function destroy_all_tokens_for_all_users() {
 		$manager = apply_filters( 'session_token_manager', 'WP_User_Meta_Session_Tokens' );
-		$manager::drop_sessions();
+		call_user_func( array( $manager, 'drop_sessions' ) );
 	}
 
 	/**