Sort search results, images, and attachments.

When providing a list of results these results should be sorted to give
consistent results. Order search results and images by the time they
were changed and attachments by there name. This fixes the Django 1.11
UnorderedObjectListWarning.

src/wiki/plugins/attachments/views.py

@@ -386,7 +386,7 @@ def get_queryset(self):
                 Q(original_filename__contains=self.query) |
                 Q(current_revision__description__contains=self.query) |
                 Q(article__current_revision__title__contains=self.query))
-        return qs
+        return qs.order_by('original_filename')
 
     def get_context_data(self, **kwargs):
         # Is this a bit of a hack? Use better inheritance?

src/wiki/plugins/images/views.py

@@ -41,7 +41,7 @@ def get_queryset(self):
                 article=self.article,
                 current_revision__deleted=False)
         images.select_related()
-        return images
+        return images.order_by('-current_revision__imagerevision__created')
 
     def get_context_data(self, **kwargs):
         kwargs.update(ArticleMixin.get_context_data(self, **kwargs))

src/wiki/views/article.py

@@ -686,15 +686,15 @@ def dispatch(self, request, *args, **kwargs):
 
     def get_queryset(self):
         if not self.query:
-            return models.Article.objects.none()
+            return models.Article.objects.none().order_by('-current_revision__created')
         articles = models.Article.objects.filter(
             Q(current_revision__title__icontains=self.query) |
             Q(current_revision__content__icontains=self.query))
         if not permissions.can_moderate(
                 models.URLPath.root().article,
                 self.request.user):
             articles = articles.active().can_read(self.request.user)
-        return articles
+        return articles.order_by('-current_revision__created')
 
     def get_context_data(self, **kwargs):
         kwargs = super(SearchView, self).get_context_data(**kwargs)