[SPARK-6369] [SQL] Uses commit coordinator to help committing Hive and Parquet tables

This PR leverages the output commit coordinator introduced in #4066 to help committing Hive and Parquet tables.

This PR extracts output commit code in `SparkHadoopWriter.commit` to `SparkHadoopMapRedUtil.commitTask`, and reuses it for committing Parquet and Hive tables on executor side.

TODO

- [ ] Add tests

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Author: Cheng Lian <lian@databricks.com>

Closes #5139 from liancheng/spark-6369 and squashes the following commits:

72eb628 [Cheng Lian] Fixes typo in javadoc
9a4b82b [Cheng Lian] Adds javadoc and addresses @aarondav's comments
dfdf3ef [Cheng Lian] Uses commit coordinator to help committing Hive and Parquet tables