[ZEPPELIN-2452] block update paragraph event on revision mode

[cloverhearts]

What is this PR for?

In revision mode using git-repository, by default all paragraphs must remain unmodifiable.
However, we are currently performing an incorrect update.

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 note and modify to paragraph and version control commit on web
2. modify to paragraph and execute
3. open your 2 browser - one browser is HEAD, and other browser move to before commit
4. insert paragarph or modify and execute.
   check update

Screenshots (if appropriate)

problem

fixed (this pr)

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 build success? https://travis-ci.org/cloverhearts/zeppelin/builds/225916461

[khalidhuseynov]

i'm getting following error during build of webapp

[INFO] /Users../zeppelin/zeppelin-web/src/app/notebook/paragraph/paragraph.controller.js
[INFO] 613:26 error Expected '!==' and instead saw '!=' eqeqeq
[INFO] 614:30 error Extra semicolon semi
[INFO] 1247:10 error Redundant double negation no-extra-boolean-cast
[INFO] 1248:13 error Extra semicolon semi

could you check it out?

[cloverhearts]

CI PASS :)

[khalidhuseynov]

LGTM

[cloverhearts]

if no more opinions, i will merge.

[khalidhuseynov]

I think this and #2289 are required in branch-0.7 as well, isn't it?