[Replacements] Prevent double increment in fixer script

It's live on e9 already, so some replacements might already contain the
correct information.

script/fixes/103_fill_new_post_replacement_fields.rb

@@ -10,10 +10,13 @@ end
 PostReplacement.select(:post_id).where(status: ["approved", "original"]).group(:post_id)
                .having("count(post_id) = 2").map(&:post_id).each do |post_id|
   replacements = PostReplacement.where(post_id: post_id).order(:status)
-  
+
   approved = replacements[0]
   original = replacements[1]
 
+  # Don't double increment
+  next if approved.uploader_id_on_approve.blank?
+
   approved.uploader_id_on_approve = original.creator_id
   approved.penalize_uploader_on_approve = true
   approved.save!