For ENG-5472, fix a crash caused by the cartographer witnessing partitions go away
For ENG-5472, make ops agents somewhat responsive at startup
For ENG-5472, handle dummy responses not having schema for a  request
For ENG-5472, based on Ning's feedback update other place that might see nodes go missing
Merge pull request #933 from VoltDB/ENG-5472

Eng 5472 Fix issues found when a joining node crashes from OOM, make stats of joining nodes not block