fix: trigger forceAlign cannot call

Author: tangjinzhou

components/trigger/Trigger.jsx

@@ -465,8 +465,8 @@ export default {
       return action.indexOf('focus') !== -1 || hideAction.indexOf('blur') !== -1
     },
     forcePopupAlign () {
-      if (this.$data.sPopupVisible && this._component && this._component.alignInstance) {
-        this._component.alignInstance.forceAlign()
+      if (this.$data.sPopupVisible && this._component && this._component.$refs.alignInstance) {
+        this._component.$refs.alignInstance.forceAlign()
       }
     },
     fireEvents (type, e) {