Revert "Update minitest on TravisCI (see if this fixes JRuby failure..."
Revert "Update minitest on TravisCI (see if this fixes JRuby failure..."

This reverts commit e40fff1d9b91af0c68c5f6bc9ba03b99fbaa379c.

honeybadger-io/honeybadger-ruby,honeybadger-io/honeybadger-ruby