Disambiguate syntax in update_shipment_state_for_canceled_orders so it can run
on MySQL and PostgreSQL.

See it break the build here: http://ci.spreecommerce.com/viewLog.html?buildId=2232&buildTypeId=bt2&tab=buildLog#_focus=372
Set deleted_at timestamp in the past for product_properties_controller +
products_controller tests

This is because MySQL's time columns don't differentiate between events which happen in the same second. PostgreSQL and SQLite do.