ParquetOutputCommitter should propagate errors when writing metadata files

There's a lot of different ways the output committer can fail, or fail to rollback after failing to write metadata files. We should decide whether metadata files are required, and fatal (I think that's reasonable if the user asked for them), and propagate without squashing exceptions.

**Reporter**: [Alex Levenson](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=alexlevenson) / @isnotinvain
#### PRs and other links:
- [GitHub Pull Request #502](https://github.com/apache/parquet-mr/pull/502)

_{**Note**: *This issue was originally created as [PARQUET-383](https://issues.apache.org/jira/browse/PARQUET-383). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}