Remove unneeded attribute alias

#790

app/models/concerns/domain/deletable.rb

@@ -1,10 +1,6 @@
 module Concerns::Domain::Deletable
   extend ActiveSupport::Concern
 
-  included do
-    alias_attribute :delete_time, :delete_at
-  end
-
   def discard
     statuses << DomainStatus::DELETE_CANDIDATE
     save

app/models/domain.rb

@@ -684,7 +684,7 @@ class Domain < ActiveRecord::Base
   end
 
   def self.delete_candidates
-    where("#{attribute_alias(:delete_time)} < ?", Time.zone.now)
+    where('delete_at < ?', Time.zone.now)
   end
 
   def self.uses_zone?(zone)

app/presenters/domain_presenter.rb

@@ -30,7 +30,7 @@ class DomainPresenter
   end
 
   def delete_date
-    view.l(domain.delete_time, format: :date) if domain.delete_time
+    view.l(domain.delete_at, format: :date) if domain.delete_at
   end
 
   def force_delete_date