[STREAMING] SPARK-1730. Make receiver store data reliably to avoid data-loss on exec...

...utor failures.

Added a new method in Receiver, ReceiverSupervisor, ReceiverSupervisorImpl to store the data
and callback a supplied function with a given argument.
https://github.com/apache/spark/tree/master/core/src/main/java/org/apache/spark/api/java/function