ENG-5694: Pass snapshot fragment sp handle to the task log during live rejoin.
ENG-5694: Set CompleteTransactionMessage's spHandle on the SPI.

The SPI sets the spHandle on the CompleteTransactionMessage when it sends them
to the replicas, but the one used on the SPI itself didn't have spHandle
set. Making sure that they all have a proper spHandle set.
ENG-5694: Pass voltroot path to the elastic join node coordinator.
Merge pull request #1294 from VoltDB/ENG-5694

ENG-5694: Pass snapshot fragment sp handle to the task log during live rejoin

r=izzy