Fix MySQL build failure

db/post_migrate/20170502101023_cleanup_namespaceless_pending_delete_projects.rb

@@ -30,7 +30,7 @@ class CleanupNamespacelessPendingDeleteProjects < ActiveRecord::Migration
   private
 
   def pending_delete_batch
-    connection.exec_query(find_batch).map{ |row| row['id'] }
+    connection.exec_query(find_batch).map{ |row| row['id'].to_i }
   end
 
   BATCH_SIZE = 5000

spec/migrations/cleanup_namespaceless_pending_delete_projects_spec.rb

@@ -15,7 +15,7 @@ describe CleanupNamespacelessPendingDeleteProjects do
       project = build(:empty_project, pending_delete: true, namespace_id: nil)
       project.save(validate: false)
 
-      expect(NamespacelessProjectDestroyWorker).to receive(:bulk_perform_async).with([[project.id.to_s]])
+      expect(NamespacelessProjectDestroyWorker).to receive(:bulk_perform_async).with([[project.id]])
 
       described_class.new.up
     end