ParquetFileWriter.appendFile does not close file handle - resource leak

Current implementation of the method ParquetFileWriter.appendFile does not close file handle.
```Java
ParquetFileReader.open(conf, file).appendTo(this);
```

My suggested fix is following:
```Java
try (ParquetFileReader reader = ParquetFileReader.open(conf, file)) {
reader.appendTo(this);
}
```

**Reporter**: [George Smith](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=cabot)
#### PRs and other links:
- [GitHub Pull Request #708](https://github.com/apache/parquet-mr/pull/708)

_{**Note**: *This issue was originally created as [PARQUET-870](https://issues.apache.org/jira/browse/PARQUET-870). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}