ZEPPELIN-1716. Error of interpreter not found is not propagated to fr…

[zjffdu]

What is this PR for?

It is introduced in ZEPPELIN-1399, we call InterpreterFactory.getInterpreter before calling Paragraph.jobRun. This PR would ignore the InterpreterException in Paragraph.isValidIntepreter

What type of PR is it?

[Bug Fix | Improvement | Feature | Documentation | Hot Fix | Refactoring]

Todos

• - Task

What is the Jira issue?

• https://issues.apache.org/jira/browse/ZEPPELIN-1716

How should this be tested?

Tested manually, see the following screenshot

Screenshots (if appropriate)

Before this PR, only see the following error in log, but not in frontend

ERROR [2016-11-28 15:16:47,378] ({qtp1471868639-17} NotebookServer.java[onMessage]:303) - Can't handle message
org.apache.zeppelin.interpreter.InterpreterException: spark.sparkr interpreter not found
    at org.apache.zeppelin.interpreter.InterpreterFactory.getInterpreter(InterpreterFactory.java:1302)
    at org.apache.zeppelin.notebook.Paragraph.isValidInterpreter(Paragraph.java:596)
    at org.apache.zeppelin.notebook.Paragraph.getMagic(Paragraph.java:586)
    at org.apache.zeppelin.socket.NotebookServer.runParagraph(NotebookServer.java:1337)
    at org.apache.zeppelin.socket.NotebookServer.onMessage(NotebookServer.java:226)
    at org.apache.zeppelin.socket.NotebookSocket.onWebSocketText(NotebookSocket.java:59)

After this PR

Questions:

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

[zjffdu]

@Leemoonsoo Please help review.

[Leemoonsoo]

Tested and LGTM. Thanks @zjffdu for the fix!
Merge to master if there're no further comments.