Fix #3323: Exclude post replacements from Mod Actions.

app/models/post_replacement.rb

@@ -56,7 +56,6 @@ class PostReplacement < ApplicationRecord
 
       if md5_changed
         post.comments.create!({creator: User.system, body: comment_replacement_message, do_not_bump_post: true}, without_protection: true)
-        ModAction.log(modaction_replacement_message)
       else
         post.queue_backup
       end
@@ -123,10 +122,6 @@ class PostReplacement < ApplicationRecord
       %("#{creator.name}":[/users/#{creator.id}] replaced this post with a new image:\n\n#{replacement_message})
     end
 
-    def modaction_replacement_message
-      "replaced post ##{post.id}:\n\n#{replacement_message}"
-    end
-
     def replacement_message
       linked_source = linked_source(replacement_url)
       linked_source_was = linked_source(post.source_was)

test/unit/post_replacement_test.rb

@@ -46,7 +46,6 @@ class PostReplacementTest < ActiveSupport::TestCase
         @post.update(source: "https://www.google.com/images/branding/googlelogo/1x/googlelogo_color_272x92dp.png")
         @post.replace!(replacement_url: "https://www.google.com/intl/en_ALL/images/logo.gif", tags: "-tag1 tag2")
         @upload = Upload.last
-        @mod_action = ModAction.last
       end
 
       context "that is then undone" do
@@ -95,10 +94,6 @@ class PostReplacementTest < ActiveSupport::TestCase
         assert_equal(false, @post.is_pending)
       end
 
-      should "log a mod action" do
-        assert_match(/replaced post ##{@post.id}/, @mod_action.description)
-      end
-
       should "leave a system comment" do
         comment = @post.comments.last
 
@@ -264,7 +259,7 @@ class PostReplacementTest < ActiveSupport::TestCase
 
       should "not queue a deletion or log a comment" do
         upload_file("#{Rails.root}/test/files/test.jpg", "test.jpg") do |file|
-          assert_no_difference(["@post.comments.count", "ModAction.count"]) do
+          assert_no_difference(["@post.comments.count"]) do
             @post.replace!(replacement_file: file, replacement_url: "")
           end
         end