[extensions-web] extension-detail: check for extension versions array.

[Yuri Konotopov <ykonotopov src gnome org>]

commit d01ebe0cb04184df7e68717bfacf0ae71e837f97
Author: Yuri Konotopov <ykonotopov gnome org>
Date:   Sun Sep 17 20:58:31 2017 +0400

    extension-detail: check for extension versions array.
    
    Download options are unneeded at review page.

 sweettooth/static/js/extensions.js |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/sweettooth/static/js/extensions.js b/sweettooth/static/js/extensions.js
index 0e1c1c0..a4246b8 100644
--- a/sweettooth/static/js/extensions.js
+++ b/sweettooth/static/js/extensions.js
@@ -47,6 +47,11 @@ define(['jquery', 'messages', 'dbus!_', 'extensionUtils', 'templates', 'paginato
                                let extension_versions = $extension.data('versions');
                                let uuid = $extension.data('uuid');
 
+                               if(!extension_versions)
+                               {
+                                       return;
+                               }
+
                                let shell_versions = Object.keys(extension_versions);
                                shell_versions.sort(extensionUtils.shellVersionCompare).reverse();