zjffdu ZEPPELIN-3796. Polluted output for spark interpreter
### What is this PR for?
This PR is to clear polluted spark interpreter output.

### What type of PR is it?
[Bug Fix]

### Todos
* [ ] - Task

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-3796

### How should this be tested?
* CI pass

### Screenshots (if appropriate)
Before
![screen shot 2018-09-27 at 12 41 47 pm](https://user-images.githubusercontent.com/164491/46123777-dadfb180-c252-11e8-9c08-1abbd44be1ca.png)

After
![screen shot 2018-09-27 at 12 41 41 pm](https://user-images.githubusercontent.com/164491/46123774-d87d5780-c252-11e8-84a0-26578b8a5eee.png)

### Questions:
* Does the licenses files need update? No
* Is there breaking changes for older versions? No
* Does this needs documentation? No

Author: Jeff Zhang <zjffdu@apache.org>

Closes #3190 from zjffdu/ZEPPELIN-3796 and squashes the following commits:

cebca39 [Jeff Zhang] ZEPPELIN-3796. Polluted output for spark interpreter
Latest commit 62e546f Sep 27, 2018