CreateQueue fails when attributes aren't passed but are changed from default

[dr3s]

https://github.com/adamw/elasticmq/blob/master/rest/rest-sqs/src/main/scala/org/elasticmq/rest/sqs/CreateQueueDirectives.scala#L47

CreateQueue doesn't take into consideration when attributes aren't passed in the request but have been changed from the defaults. This differs from AWS SQS behavior. If attributes aren't passed, they should not be considered in determining whether the queue name exists exception is thrown.

[adamw]

Ah :) maybe you could try writing a PR? thanks!