[SPARK-4908][SQL] Prevent multiple concurrent hive native commands

This is just a quick fix that locks when calling `runHive`.  If we can find a way to avoid the error without a global lock that would be better.

Author: Michael Armbrust <michael@databricks.com>

Closes #3834 from marmbrus/hiveConcurrency and squashes the following commits:

bf25300 [Michael Armbrust] prevent multiple concurrent hive native commands