[polari] joinDialog: Fix variable name

[Florian Müllner <fmuellner src gnome org>]

commit 54e88f37becd1f092ac967eb8f41b903b3fec92b
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Oct 24 02:38:12 2015 +0200

    joinDialog: Fix variable name
    
    Fallout from commit 84ff117eb.

 src/joinDialog.js |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/joinDialog.js b/src/joinDialog.js
index 30ac420..51cd644 100644
--- a/src/joinDialog.js
+++ b/src/joinDialog.js
@@ -145,7 +145,7 @@ const JoinDialog = new Lang.Class({
     _onConfirmClicked: function() {
         if (this._page == DialogPage.MAIN) {
             this._joinRoom();
-            this._widget.destroy();
+            this.widget.destroy();
         } else {
             this._details.save();
             this._setPage(DialogPage.MAIN);