[extensions-web] extensions: Fix the case of trying to fetch an incompatible extension

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

commit c54bfd2b8ddea346bcbf47bcd7e0ecdf85e57355
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Mar 29 19:33:38 2012 -0400

    extensions: Fix the case of trying to fetch an incompatible extension
    
    404 instead of 500, because Django is super inconsistent :(

 sweettooth/extensions/views.py |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)
---
diff --git a/sweettooth/extensions/views.py b/sweettooth/extensions/views.py
index 9559cae..fa9846d 100644
--- a/sweettooth/extensions/views.py
+++ b/sweettooth/extensions/views.py
@@ -60,10 +60,11 @@ def shell_download(request, uuid):
         if not shell_versions:
             raise Http404()
 
-        try:
-            version = extension.visible_versions.filter(shell_versions__in=shell_versions).order_by('-version')[0]
-        except models.ExtensionVersion.DoesNotExist:
+        versions = extension.visible_versions.filter(shell_versions__in=shell_versions)
+        if versions.count() < 1:
             raise Http404()
+        else:
+            version = versions.order_by('-version')[0]
 
     extension.downloads += 1
     extension.save(replace_metadata_json=False)