Use rc-util Portal

Author: yesmeck

package.json

@@ -62,6 +62,6 @@
     "prop-types": "15.x",
     "rc-align": "2.x",
     "rc-animate": "2.x",
-    "rc-util": "4.x"
+    "rc-util": "^4.1.0"
   }
 }

src/Portal.js

@@ -7,7 +7,7 @@ import addEventListener from 'rc-util/lib/Dom/addEventListener';
 import Popup from './Popup';
 import { getAlignFromPlacement, getPopupClassNameFromAlign } from './utils';
 import getContainerRenderMixin from 'rc-util/lib/getContainerRenderMixin';
-import Portal from './Portal';
+import Portal from 'rc-util/lib/Portal';
 
 function noop() {
 }