set only the pinned post if there is one to pin.

fet2020/fet2020/views.py

@@ -18,11 +18,7 @@ def index(request):
 
     # set the pinned post
     pinned_post = Post.articles.pinned()
-    if not pinned_post:
-        # if a pinned post does not exist, take the last published one.
-        if len(posts) >= 1:
-            pinned_post = posts.popleft()
-    else:
+    if pinned_post:
         # remove the pinned post
         posts.remove(pinned_post)