Remove PubSubHubbub-related columns from accounts table (#16170)

spec/services/process_mentions_service_spec.rb

@@ -7,37 +7,6 @@ RSpec.describe ProcessMentionsService, type: :service do
 
   subject { ProcessMentionsService.new }
 
-  context 'OStatus with public toot' do
-    let(:remote_user) { Fabricate(:account, username: 'remote_user', protocol: :ostatus, domain: 'example.com', salmon_url: 'http://salmon.example.com') }
-
-    before do
-      stub_request(:post, remote_user.salmon_url)
-      subject.call(status)
-    end
-
-    it 'does not create a mention' do
-      expect(remote_user.mentions.where(status: status).count).to eq 0
-    end
-  end
-
-  context 'OStatus with private toot' do
-    let(:visibility)  { :private }
-    let(:remote_user) { Fabricate(:account, username: 'remote_user', protocol: :ostatus, domain: 'example.com', salmon_url: 'http://salmon.example.com') }
-
-    before do
-      stub_request(:post, remote_user.salmon_url)
-      subject.call(status)
-    end
-
-    it 'does not create a mention' do
-      expect(remote_user.mentions.where(status: status).count).to eq 0
-    end
-
-    it 'does not post to remote user\'s Salmon end point' do
-      expect(a_request(:post, remote_user.salmon_url)).to_not have_been_made
-    end
-  end
-
   context 'ActivityPub' do
     context do
       let(:remote_user) { Fabricate(:account, username: 'remote_user', protocol: :activitypub, domain: 'example.com', inbox_url: 'http://example.com/inbox') }