store cache file in a temp dir suffixed by client id to avoid error i…

…f several websites are on the same server

Helper/MangopayHelper.php

@@ -28,7 +28,7 @@ public function __construct($clientId, $clientPassword, $baseUrl, EventDispatche
         parent::__construct();
         $this->Config->ClientId = $clientId;
         $this->Config->ClientPassword = $clientPassword;
-        $this->Config->TemporaryFolder = sys_get_temp_dir();
+        $this->Config->TemporaryFolder = sys_get_temp_dir().'/'.$clientId;
         $this->Config->BaseUrl = $baseUrl;
         $this->Config->DebugMode = $debug;
         $this->dispatcher = $dispatcher;