[Cleanup] Remove merge_version?

app/models/post.rb

@@ -1368,11 +1368,6 @@ class Post < ApplicationRecord
       saved_change_to_rating? || saved_change_to_source? || saved_change_to_parent_id? || saved_change_to_tag_string? || saved_change_to_locked_tags? || saved_change_to_description?
     end
 
-    def merge_version?
-      prev = versions.last
-      prev && prev.updater_id == CurrentUser.user.id && prev.updated_at > 1.hour.ago
-    end
-
     def create_new_version
       # This function name is misleading, this directly creates the version.
       # Previously there was a queue involved, now there isn't.

test/unit/artist_test.rb

@@ -276,7 +276,6 @@ class ArtistTest < ActiveSupport::TestCase
     context "when saving" do
       setup do
         @artist = FactoryBot.create(:artist, url_string: "http://foo.com")
-        @artist.stubs(:merge_version?).returns(false)
       end
 
       should "create a new version when an url is added" do

test/unit/note_test.rb

@@ -13,19 +13,6 @@ class NoteTest < ActiveSupport::TestCase
       CurrentUser.ip_addr = nil
     end
 
-    context "#merge_version" do
-      setup do
-        @post = FactoryBot.create(:post)
-        @note = FactoryBot.create(:note, :post => @post)
-      end
-
-      should "not increment version" do
-        @note.update(:x => 100)       
-        assert_equal(1, @note.versions.count)
-        assert_equal(1, @note.versions.first.version)
-      end
-    end
-
     context "for a post that already has a note" do
       setup do
         @post = FactoryBot.create(:post)
@@ -115,7 +102,6 @@ class NoteTest < ActiveSupport::TestCase
       setup do
         @post = FactoryBot.create(:post, :image_width => 1000, :image_height => 1000)
         @note = FactoryBot.create(:note, :post => @post)
-        @note.stubs(:merge_version?).returns(false)
       end
 
       should "increment the updater's note_update_count" do

test/unit/user_revert_test.rb

@@ -11,7 +11,6 @@ class UserRevertTest < ActiveSupport::TestCase
         @post = create(:post, :tag_string => "aaa bbb ccc", :rating => "q", :source => "xyz")
       end
 
-      @post.stubs(:merge_version?).returns(false)
       CurrentUser.scoped(@user) do
         @post.update(:tag_string => "bbb ccc xxx", :source => "", :rating => "e")
       end