[SPARK-15004][SQL] Remove zookeeper service discovery code in thrift-server

[rxin]

What changes were proposed in this pull request?

We recently inlined Hive's thrift server code in SPARK-15004. This patch removes the code related to zookeeper service discovery, Tez, and Hive on Spark, since they are irrelevant.

How was this patch tested?

N/A - removing dead code

[rxin]

cc @davies

[SparkQA]

Test build #57345 has finished for PR 12780 at commit 524bc25.

• This patch fails to build.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #57353 has finished for PR 12780 at commit 58f925a.

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

[davies]

@rxin The zookeeper things is actually useful for HA or load balancing. If we really want to remove it, this looks good to me.

[rxin]

Merging this. Thanks.