Split hive.root.logger separately to make it compatible with log4j1.x

With new Log4j2.x specifying logger name and log level together will not work.

With old logger following will work
--hiveconf hive.root.logger=DEBUG,console

But with new logger we should specify logger and level separately
--hiveconf hive.root.logger=console --hiveconf hive.log.level=DEBUG

We can do this change internally for users still using the old configs.