Show error message in UnhandledWebDriverError

(Thanks to @slowbro)

Author: whhone

lib/remote/HttpCommandExecutor.php

@@ -233,8 +233,8 @@ protected static function curl(
     }
 
     $message = null;
-    if (is_array($results) && array_key_exists('message', $results)) {
-      $message = $results['message'];
+    if (is_array($value) && array_key_exists('message', $value)) {
+      $message = $value['message'];
     }
 
     $sessionId = null;