Revert "[SPARK-2410][SQL] Merging Hive Thrift/JDBC server"

This reverts commit f6ff2a61d00d12481bfb211ae13d6992daacdcc2.
SPARK-2651: Add maven scalastyle plugin

Can be run as: "mvn scalastyle:check"

Author: Rahul Singhal <rahul.singhal@guavus.com>

Closes #1550 from rahulsinghaliitd/SPARK-2651 and squashes the following commits:

53748dd [Rahul Singhal] SPARK-2651: Add maven scalastyle plugin
[SPARK-1550] [PySpark] Allow SparkContext creation after failed attempts

This addresses a PySpark issue where a failed attempt to construct SparkContext would prevent any future SparkContext creation.

Author: Josh Rosen <joshrosen@apache.org>

Closes #1606 from JoshRosen/SPARK-1550 and squashes the following commits:

ec7fadc [Josh Rosen] [SPARK-1550] [PySpark] Allow SparkContext creation after failed attempts
SPARK-2686 Add Length support to Spark SQL and HQL and Strlen support to SQL

Rolled back changes that somehow got in from other PR's

SPARK-2686 after M. Armbrust comments

Rollback addition of length method for HiveQL since incompatible with Hive default encoding

SPARK-2686 Address comments  from chenghao-intel