[Hot Fix] Fix flaky ZeppelinIT build

[prabhjyotsingh]

What is this PR for?

Most of the builds are failing for ZeppelinIT at testSparkInterpreterDependencyLoading:243, as the previous line's testDepRemoveBtn.click() is taking it to a different page.

What type of PR is it?

[Hot Fix]

Todos

• - Change all add/remove dependencies/property's div to button
• - make relevant change in selenium test case.

What is the Jira issue?

ZEPPELIN-950

How should this be tested?

CI should pass

Questions:

• Does the licenses files need update? N/A
• Is there breaking changes for older versions? N/A
• Does this needs documentation? N/A

[prabhjyotsingh]

Tried it 4 different times

• https://travis-ci.org/apache/incubator-zeppelin/builds/135110386
• https://travis-ci.org/apache/incubator-zeppelin/builds/135119542
• https://travis-ci.org/apache/incubator-zeppelin/builds/135124485
• https://travis-ci.org/apache/incubator-zeppelin/builds/135128424

Every time *.7 passes, but fails for either spark download or npm install.

[felixcheung]

thanks! we should probably look into download/network errors too.
LGTM

[prabhjyotsingh]

Sure, I'll try to figure something out for npm related network error(s).

I'll merge this if no more discussion.