Fix explore page title style.

The "explore-page" css class was removed at some point but it's needed for
correct placement of the "Explore" title (since this page doesn't have hot,
new, etc tabs.)

r2/r2/controllers/front.py

@@ -163,6 +163,7 @@ class FrontController(RedditController, OAuth2ResourceController):
         return BoringPage(_("explore"),
                           show_sidebar=True,
                           show_chooser=True,
+                          page_classes=['explore-page'],
                           content=content).render()
  
     @validate(article=VLink('article'))