DisallowConcurrentExecution attribute doesn't seem to stop concurrent execution

[ollyw]

When scheduling a single durable job with multiple triggers, even through I add the DisallowConcurrentExecution attribute to the job, concurrent execution happens.

I thought that this was an issue with the Quartz libraries originally, but the ObjectUtil.isAttributePresent correctly detects my job having the attribute, and when I look at the code to actually enforce it, it is in the job store, so implemented in quartznet-mongodb.

(Great job with mongo-quartz, BTW!)