Account for new Spark HadoopRDD API.

Also, for non-partitioned tables stored in Hadoop, moves row deserialization from
processPartition() to preprocessRDD(). This makes it more consistent with partitioned
table reads/processing, and allows us to annotate HiveConf as transient, which
should reduce Spark task sizes.
Remove Kryo references in SharkEnv. The ShuffleSerializer is explicitly specified as the object serializer for shuffle ops.
Get Shark to compile with latest Spark master.