[CE->EE] Fix rubocop

see https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/13

db/migrate/20170403141442_add_elasticsearch_experimental_indexer_to_application_settings.rb

+# rubocop:disable Migration/SaferBooleanColumn
 class AddElasticsearchExperimentalIndexerToApplicationSettings < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

db/migrate/20170625171421_add_slack_to_application_settings.rb

 # See http://doc.gitlab.com/ce/development/migration_style_guide.html
 # for more information on how to write migrations for GitLab.
-
+# rubocop:disable Migration/SaferBooleanColumn
 class AddSlackToApplicationSettings < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers