Run mvn clean in CI

Currently parquet-mr CI does not run `mvn clean`, modules without changes are not recompiled each time.

**Reporter**: [Qinghui Xu](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=q.xu) / @qinghui-xu
**Assignee**: [Qinghui Xu](https://issues.apache.org/jira/secure/ViewProfile.jspa?name=q.xu) / @qinghui-xu
#### Related issues:
- [Invoke mvn clean in Travis](https://github.com/apache/parquet-java/issues/1599) (is duplicated by)

_{**Note**: *This issue was originally created as [PARQUET-1900](https://issues.apache.org/jira/browse/PARQUET-1900). Please see the [migration documentation](https://issues.apache.org/jira/browse/PARQUET-2502) for further details.*}