[ZEPPELIN-4646]. zeppelin-server doesn't need scala
[ZEPPELIN-4646]. zeppelin-server doesn't need scala

### What is this PR for?

Trivial change which just remove scala dependency from zeppelin-server because it doesn't need these.

### What type of PR is it?
[ Improvement ]

### Todos
* [ ] - Task

### What is the Jira issue?
* https://issues.apache.org/jira/browse/ZEPPELIN-4646

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

### Screenshots (if appropriate)

### 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 #3664 from zjffdu/ZEPPELIN-4646 and squashes the following commits:

479066784 [Jeff Zhang] [ZEPPELIN-4646]. zeppelin-server doesn't need scala

jongyoul/zeppelin,apache/zeppelin,fogbeam/zeppelin_mirror,jongyoul/incubator-zeppelin,zjffdu/zeppelin,apache/incubator-zeppelin,Leemoonsoo/incubator-zeppelin,Leemoonsoo/zeppelin,fogbeam/zeppelin_mirror,joroKr21/incubator-zeppelin,hammertank/zeppelin,prabhjyotsingh/zeppelin,hammertank/zeppelin,prabhjyotsingh/incubator-zeppelin,Leemoonsoo/zeppelin,jongyoul/zeppelin,Leemoonsoo/incubator-zeppelin,Leemoonsoo/zeppelin,VipinRathor/zeppelin,fogbeam/zeppelin_mirror,apache/zeppelin,joroKr21/incubator-zeppelin,jongyoul/zeppelin,VipinRathor/zeppelin,prabhjyotsingh/incubator-zeppelin,hammertank/zeppelin,prabhjyotsingh/zeppelin,hammertank/zeppelin,hammertank/zeppelin,apache/zeppelin,prabhjyotsingh/incubator-zeppelin,prabhjyotsingh/zeppelin,apache/zeppelin,fogbeam/zeppelin_mirror,apache/incubator-zeppelin,zjffdu/zeppelin,VipinRathor/zeppelin,Leemoonsoo/zeppelin,prabhjyotsingh/incubator-zeppelin,apache/incubator-zeppelin,joroKr21/incubator-zeppelin,prabhjyotsingh/zeppelin,VipinRathor/zeppelin,jongyoul/incubator-zeppelin,prabhjyotsingh/zeppelin,joroKr21/incubator-zeppelin,joroKr21/incubator-zeppelin,fogbeam/zeppelin_mirror,Leemoonsoo/zeppelin,prabhjyotsingh/zeppelin,jongyoul/zeppelin,Leemoonsoo/zeppelin,VipinRathor/zeppelin,jongyoul/incubator-zeppelin,VipinRathor/zeppelin,VipinRathor/zeppelin,prabhjyotsingh/incubator-zeppelin,jongyoul/zeppelin,hammertank/zeppelin,jongyoul/zeppelin,zjffdu/zeppelin,joroKr21/incubator-zeppelin,apache/incubator-zeppelin,apache/zeppelin,zjffdu/zeppelin,prabhjyotsingh/zeppelin,jongyoul/incubator-zeppelin,jongyoul/incubator-zeppelin,prabhjyotsingh/incubator-zeppelin,Leemoonsoo/incubator-zeppelin,Leemoonsoo/incubator-zeppelin,Leemoonsoo/zeppelin,Leemoonsoo/zeppelin,joroKr21/incubator-zeppelin,Leemoonsoo/incubator-zeppelin,zjffdu/zeppelin,fogbeam/zeppelin_mirror,zjffdu/zeppelin,fogbeam/zeppelin_mirror,apache/zeppelin,jongyoul/incubator-zeppelin,apache/incubator-zeppelin,joroKr21/incubator-zeppelin,apache/incubator-zeppelin,hammertank/zeppelin,jongyoul/zeppelin,Leemoonsoo/incubator-zeppelin,zjffdu/zeppelin,apache/zeppelin