ENG-4535: Add an accessor to get the partition ID to the Initiator.
ENG-4535: Change the JoinCoordinator interface to take a map of local partitions
to local site HSIDs.
ENG-4535: Add a method to ElasticHashinator to find the predecessors of a
partition on the ring.
ENG-4535: Add multiple snapshot sink HSIDs to the RejoinMessage.
Add a new line to the EOF of RejoinSiteProcessor.
ENG-4535: Use multiple snapshot sinks in the ElasticJoinProducer for the same
stream snapshot, since it is possible that a joining partition needs to get data
from multiple sources.
Respond with correct dummy fragment response during elastic join for sys proc.
ENG-4535: Set the correct joining state in RealVoltDB so that if the node has
more than one site, the joined sites can handle snapshot fragments correctly.
ENG-4535: Modify post-snapshot action to update the Java and EE hashinators with
multiple sites per host.
ENG-4535: Add more debug log messages to ElasticJoinProducer.
ENG-4535: Add more log messages in StreamSnapshotWritePlan.
ENG-4535: Create PostSnapshotTask and run it on each site after the snapshot
tasks, even if the site didn't do any snapshot task.
Refactor RejoinProducer to get rid of the firstWork trick.

It now polls the snapshot sink to see if the first snapshot block is ready, if
not, the producer will queue itself onto the site queue and retry again. This
basically spins so CPU usage may not be low while the site is waiting for data,
but the code is much simpler.
Refactor ElasticJoinProducer to get rid of the firtWork hack.

Just spin on the site thread until the first snapshot data block arrives, then
block restore all partitioned table data.
Fix end of stream detection during rejoin bug introduced by the previous
refactoring.
Fix end of stream detection during join bug introduced by the previous
refactoring.
Simplify TestRejoinEndToEnd because IV2 is always on now.
Merge pull request #466 from VoltDB/ENG-4535

ENG-4535: Blocking move partitioned table data for multiple partitions