Fix rubocop issues

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

db/migrate/20160718210912_add_ldap_sync_state_to_groups.rb

 # Migration type: online without errors (works on previous version and new one)
 # rubocop:disable Migration/AddColumnWithDefaultToLargeTable
 # rubocop:disable Migration/Datetime
+# rubocop:disable Migration/UpdateLargeTable
 class AddLdapSyncStateToGroups < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
   disable_ddl_transaction!

db/migrate/20160831231325_update_mirror_when_empty_import_url_in_projects.rb

 # rubocop:disable Migration/UpdateColumnInBatches
+# rubocop:disable Migration/UpdateLargeTable
 class UpdateMirrorWhenEmptyImportUrlInProjects < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

db/migrate/20161230123835_add_squash_to_merge_requests.rb

 # rubocop:disable Migration/AddColumnWithDefaultToLargeTable
+# rubocop:disable Migration/UpdateLargeTable
 class AddSquashToMergeRequests < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
   disable_ddl_transaction!

db/migrate/20170118200338_convert_projects_repository_size_limit_to_bytes.rb

 # rubocop:disable Migration/UpdateColumnInBatches
+# rubocop:disable Migration/UpdateLargeTable
 class ConvertProjectsRepositorySizeLimitToBytes < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

db/migrate/20170118200412_convert_namespaces_repository_size_limit_to_bytes.rb

 # rubocop:disable Migration/UpdateColumnInBatches
+# rubocop:disable Migration/UpdateLargeTable
 class ConvertNamespacesRepositorySizeLimitToBytes < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

db/migrate/20170120123345_add_column_auditor_to_users.rb

@@ -2,6 +2,7 @@
 # for more information on how to write migrations for GitLab.
 
 # rubocop:disable Migration/AddColumnWithDefaultToLargeTable
+# rubocop:disable Migration/UpdateLargeTable
 class AddColumnAuditorToUsers < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

db/migrate/20170130113559_add_sync_schedule_to_projects_and_remote_projects.rb

 # rubocop:disable Migration/AddColumnWithDefaultToLargeTable
+# rubocop:disable Migration/UpdateLargeTable
 class AddSyncScheduleToProjectsAndRemoteProjects < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
 

spec/requests/api/helpers_spec.rb

@@ -233,7 +233,6 @@ describe API::Helpers do
     end
   end
 
-
   describe '.handle_api_exception' do
     before do
       allow_any_instance_of(self.class).to receive(:sentry_enabled?).and_return(true)