[SPARK-20120][SQL] spark-sql support silent mode

## What changes were proposed in this pull request?

It is similar to Hive silent mode, just show the query result. see: [Hive LanguageManual+Cli](https://cwiki.apache.org/confluence/display/Hive/LanguageManual+Cli) and [the implementation of Hive silent mode](https://github.com/apache/hive/blob/release-1.2.1/ql/src/java/org/apache/hadoop/hive/ql/session/SessionState.java#L948-L950).

This PR set the Logger level to `WARN` to get similar result.

## How was this patch tested?

manual tests

![manual test spark sql silent mode](https://cloud.githubusercontent.com/assets/5399861/24390165/989b7780-13b9-11e7-8496-6e68f55757e3.gif)

Author: Yuming Wang <wgyumg@gmail.com>

Closes #17449 from wangyum/SPARK-20120.