Don't send changeset comment notifications to deleted users

app/controllers/changeset_controller.rb

@@ -327,7 +327,7 @@ class ChangesetController < ApplicationController
                                         :author => @user)
 
     # Notify current subscribers of the new comment
-    changeset.subscribers.each do |user|
+    changeset.subscribers.visible.each do |user|
       if @user != user
         Notifier.changeset_comment_notification(comment, user).deliver_now
       end

test/fixtures/changesets_subscribers.yml

@@ -5,3 +5,11 @@ t1:
 t2:
   changeset_id: 8
   subscriber_id: 1
+
+t3:
+  changeset_id: 8
+  subscriber_id: 10
+
+t4:
+  changeset_id: 8
+  subscriber_id: 11