[gnome-builder/gnome-builder-3-26] html-preview: fix use from callback

[Christian Hergert <chergert src gnome org>]

commit 90d135d67789fdbfdab0ddd3bc52eaac7cfe56d4
Author: Christian Hergert <chergert redhat com>
Date:   Thu Sep 21 01:31:39 2017 -0700

    html-preview: fix use from callback

 .../html-preview/html_preview_plugin/__init__.py   |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/plugins/html-preview/html_preview_plugin/__init__.py 
b/plugins/html-preview/html_preview_plugin/__init__.py
index e03215c..3f1a320 100644
--- a/plugins/html-preview/html_preview_plugin/__init__.py
+++ b/plugins/html-preview/html_preview_plugin/__init__.py
@@ -253,7 +253,7 @@ class HtmlPreviewAddin(GObject.Object, Ide.EditorViewAddin):
 
         return sphinx_builddir
 
-    def preview_activated(self):
+    def preview_activated(self, *args):
         global can_preview_rst
 
         if self.view is None: