add_comments: Remove warning about writing scores first

This warning was no longer true--any missing scores are automatically
calculated and updated.

We actually have the opposite issue--the CommentTree must be updated
before writing scores because the QA score reads it.

r2/r2/lib/comment_tree.py

@@ -52,8 +52,6 @@ def add_comments(comments):
         timer = g.stats.get_timer('comment_tree.add.1')
         timer.start()
 
-        # write scores before CommentTree because the scores must exist for all
-        # comments in the tree
         for sort in ("_controversy", "_confidence", "_score"):
             scores_by_comment = {
                 comment._id36: getattr(comment, sort)