More controller specs (#2561)

* Add render_views in more places

* Delegate methods from account to user with allow nil true, so that admin accounts show view renders when missing a user

* Use actual account instances in authorize follow controller spec

spec/controllers/following_accounts_controller_spec.rb

@@ -2,6 +2,7 @@ require 'rails_helper'
 
 describe FollowingAccountsController do
   render_views
+
   let(:alice) { Fabricate(:account, username: 'alice') }
 
   describe 'GET #index' do