Default region not respected on RDS instance creation

[prozach]

With region = us-west-2 configured in puppetlabs_aws_configuration.ini, the rds_instance type fails to create the RDS instance with an error like so: Error: Could not set 'present' on ensure: missing region; use :region option or export region name to ENV['AWS_REGION']. Its possible that this is the case for other aws resources as well, but the documentation seems to indicate that region will be selected from the default configuration if the region => param is not set on the resource.