[ZEPPELIN-2452] Can not handle message in revision mode on web.

[cloverhearts]

What is this PR for?

Requests interpreter editor mode information in revision mode.
However, no information is needed in revision mode.
Produces misleading logs with misleading requests to the server.

ERROR [2017-04-26 18:07:48,718] ({qtp1273765644-60} NotebookServer.java[onMessage]:383) - Can't handle message
java.lang.NullPointerException
ERROR [2017-04-26 18:07:49,081] ({qtp1273765644-109} NotebookServer.java[onMessage]:383) - Can't handle message
java.lang.NullPointerException
ERROR [2017-04-26 18:07:49,083] ({qtp1273765644-14} NotebookServer.java[onMessage]:383) - Can't handle message
java.lang.NullPointerException

This log is requested as many as the number of paragraphs contained in the note.

What type of PR is it?

Bug fix

What is the Jira issue?

https://issues.apache.org/jira/browse/ZEPPELIN-2452

How should this be tested?

1. Create a git-repo based note. (Supported by default)
2. Modify the paragraph and commit.
3. Go to the committed revision.
4. Reload the page.
5. Check the server logs.

NotebookServer.java[onMessage]:383) - Can't handle message
java.lang.NullPointerException

Questions:

• Does the licenses files need update? no
• Is there breaking changes for older versions? no
• Does this needs documentation? no

[Leemoonsoo]

Could you make CI green https://travis-ci.org/cloverhearts/zeppelin/builds/225928425?

[cloverhearts]

@Leemoonsoo Okay :) i will

[khalidhuseynov]

i'm getting below error in web part during build here as well

[INFO] /Users../zeppelin/zeppelin-myrepo/incubator-zeppelin/zeppelin-web/src/app/notebook/paragraph/paragraph.controller.js
[INFO]   846:13  error  Expected indentation of 10 spaces but found 12  indent
[INFO]   849:11  error  Expected indentation of 8 spaces but found 10   indent

could you check it as well

[cloverhearts]

@khalidhuseynov Thank you :)

[cloverhearts]

CI PASS :)

[khalidhuseynov]

LGTM

[cloverhearts]

if no more opinions, i will merge.