bugfix: uncaught exception when ws fails or times out handshake

lib/utils/ws-requestor.js

@@ -109,8 +109,10 @@ class WsRequestor extends BaseRequestor {
 
   close() {
     this.logger.info('WsRequestor: closing socket');
-    this.ws && this.ws.close();
-    this.ws.removeAllListeners();
+    if (this.ws) {
+      this.ws.close();
+      this.ws.removeAllListeners();
+    }
   }
 
   _connect() {