fix message

components/message/index.jsx

@@ -4,14 +4,17 @@ import Notification from 'rc-notification';
 let defaultDuration = 1.5;
 let top;
 
+var messageInstance;
+
 function getMessageInstance() {
-  return Notification.newInstance({
+  messageInstance = messageInstance || Notification.newInstance({
     prefixCls: 'ant-message',
     transitionName: 'move-up',
     style: {
       top: top
     }  // 覆盖原来的样式
   });
+  return messageInstance;
 }
 
 function notice(content, duration = defaultDuration, type) {
@@ -21,7 +24,6 @@ function notice(content, duration = defaultDuration, type) {
     'error': 'anticon-exclamation-circle ant-message-error'
   })[type];
   getMessageInstance().notice({
-    key: 'simpleMessage',
     duration: duration,
     style: {},
     content: <div className="ant-message-custom-content">