Plugging memory leak

Apparently assigning a property to an object will prevent the object from being destroyed.
Thanks to @igorw to finding this memory leak

src/Ratchet/Server/IoServer.php

@@ -87,6 +87,8 @@ class IoServer {
         } catch (\Exception $e) {
             $this->handleError($e, $conn);
         }
+
+        unset($conn->decor);
     }
 
     public function handleError(\Exception $e, $conn) {