[extensions-web] extensions: Check if the screenshot exists before using it

[Jasper St. Pierre <jstpierre src gnome org>]

commit d501ceb87712a63f1f5e972a63ceb4b9763d27d5
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Nov 14 08:46:03 2016 -0800

    extensions: Check if the screenshot exists before using it

 sweettooth/extensions/views.py |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/sweettooth/extensions/views.py b/sweettooth/extensions/views.py
index 5c9e247..1543ace 100644
--- a/sweettooth/extensions/views.py
+++ b/sweettooth/extensions/views.py
@@ -321,7 +321,7 @@ def ajax_details(extension, version=None):
                    description = extension.description,
                    link = extension.get_absolute_url(),
                    icon = extension.icon.url,
-                   screenshot = extension.screenshot.url,
+                   screenshot = extension.screenshot.url if extension.screenshot else None,
                    shell_version_map = extension.visible_shell_version_map)
 
     if version is not None: