[SPARK-30164][TESTS][DOCS] Exclude Hive domain in Unidoc build explicitly

[HyukjinKwon]

What changes were proposed in this pull request?

This PR proposes to exclude Unidoc checking in Hive domain. We don't publish this as a part of Spark documentation (see also https://github.com/apache/spark/blob/master/docs/_plugins/copy_api_dirs.rb#L30) and most of them are copy of Hive thrift server so that we can officially use Hive 2.3 release.

It doesn't much make sense to check the documentation generation against another domain, and that we don't use in documentation publish.

Why are the changes needed?

To avoid unnecessary computation.

Does this PR introduce any user-facing change?

No.

How was this patch tested?

By Jenkins:

========================================================================
Building Spark
========================================================================
[info] Building Spark using SBT with these arguments:  -Phadoop-2.7 -Phive-2.3 -Phive -Pmesos -Pkubernetes -Phive-thriftserver -Phadoop-cloud -Pkinesis-asl -Pspark-ganglia-lgpl -Pyarn test:package streaming-kinesis-asl-assembly/assembly
...


========================================================================
Building Unidoc API Documentation
========================================================================
[info] Building Spark unidoc using SBT with these arguments:  -Phadoop-2.7 -Phive-2.3 -Phive -Pmesos -Pkubernetes -Phive-thriftserver -Phadoop-cloud -Pkinesis-asl -Pspark-ganglia-lgpl -Pyarn unidoc
...
[info] Main Java API documentation successful.
...
[info] Main Scala API documentation successful.

[HyukjinKwon]

cc @gengliangwang, @dongjoon-hyun, @srowen, @wangyum

[SparkQA]

Test build #115002 has finished for PR 26800 at commit 8c06512.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

Okay, the root cause of the test failure was #26788 (comment).

But I am going to still merge this. It will at least save some computation.

[HyukjinKwon]

Merged to master.

[dongjoon-hyun]

+1, late LGTM.