Typo, and lack of VPC support for RDS/Restore from snapshot

[cbake6807]

There seems to be a typo in the param['engine'] at the very end of this line https://github.com/rightscale/right_aws/blob/master/lib/rds/right_rds_interface.rb#L799

unless params[:enginel].right_blank?

should be

unless params[:engine].right_blank?

Also, the request_hash doesn't include an overridable PubliclyAccessible key, for setting the value to FALSE and creating the RDS instance in a VPC

http://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_RestoreDBInstanceFromDBSnapshot.html

Thanks, Chris