comments: add check for empty comments

debexpo/templates/index/index.mako

@@ -31,7 +31,7 @@
 <p>If you are curious about <em>Debexpo</em>, the software which is running this site, you can <a
         href="http://wiki.debian.org/Debexpo">read more about Debexpo on the Debian Wiki</a>.</p>
 <h3>best comment </h3>
-%if hasattr(c,'best_comment'):
+%if hasattr(c,'best_comment') and c.best_comment is not None:
 
     <% comment=c.best_comment %>
     <% id=c.best_comment.package_version_id %>
@@ -40,7 +40,7 @@
 
 %endif
 <h3>last comment</h3>
-%if hasattr(c,'last_comment'):
+%if hasattr(c,'last_comment') and c.last_comment is not None:
     <% comment=c.last_comment %>
     <%include file='../comments/comments.mako'args='id=1,package_version_id=c.last_comment.package_version_id,comment=c.last_comment'/>