Merge branch 'cs-upgrade-database-cleaner' into 'master'

Upgrade database_cleaner from 1.4.1 to 1.5.3.

This includes support for Rails 5 without deprecations warnings. Working toward #14286.

Changelog: https://github.com/DatabaseCleaner/database_cleaner/blob/master/History.rdoc#153-2016-04-22

See merge request !5505