Share a broadcasted Configuration for scans of Hive-partitioned tables stored on disk.

Previously, there was one broadcasted Configuration for each HadoopRDD created for a Hive partition that's stored on disk - e.g., for a table scan over 1000 partitions, there are 1000 Configuration broadcasts.
This change uses the HadoopFileRDD, so that there is one broadcasted Configuration shared across multiple HadoopRDDs created for the table scan.