Disable transaction in specs for some migrations

spec/lib/gitlab/database/rename_reserved_paths_migration/v1/rename_namespaces_spec.rb

 require 'spec_helper'
-describe Gitlab::Database::RenameReservedPathsMigration::V1::RenameNamespaces do
+describe Gitlab::Database::RenameReservedPathsMigration::V1::RenameNamespaces, :truncate do
   let(:migration) { FakeRenameReservedPathMigrationV1.new }
   let(:subject) { described_class.new(['the-path'], migration) }

spec/migrations/migrate_user_project_view_spec.rb

@@ -3,7 +3,7 @@
 require 'spec_helper'
 require Rails.root.join('db', 'post_migrate', '20170406142253_migrate_user_project_view.rb')
-describe MigrateUserProjectView do
+describe MigrateUserProjectView, :truncate do
   let(:migration) { described_class.new }
   let!(:user) { create(:user) }