For ENG-6060, fix findbug error of exception not being thrown
For ENG-6062, handle cases where pushed export buffer is null
Merge pull request #1237 from VoltDB/ENG-6062

For ENG-6062, handle cases where pushed export buffer is null
Merge pull request #1236 from VoltDB/ENG-6060

For ENG-6060, fix findbug error of exception not being thrown