Why does Zeppelin not include org.apache.hadoop:hadoop-common file ?

Hi, I was wondering why Zeppelin does not have `org.apache.hadoop:hadoop-common:{version}` when installing Zeppelin server. 

I know that the file is not necessary for all the cases, but for JDBC kerberos it is needed.

I notice that the scope is "provided" in pom.xml file which means that I need to add it myself.

• https://github.com/apache/zeppelin/blob/v0.9.0-docker/jdbc/pom.xml#L88-L93

Well if it is not necessary jar file, then how about adding comments to official document that in order to use `zeppelin.jdbc.auth.type` as `KERBEROS` you need to add custom dependency that matches your hadoop version (2 or 3)

• https://zeppelin.apache.org/docs/0.10.0/interpreter/jdbc.html#more-properties