Setting zeppelin.jdbc.auth.type to KERBEROS didn't work

According to the JDBC Interpreter document (https://github.com/apache/zeppelin/blob/master/docs/interpreter/jdbc.md), we should use zeppelin.jdbc.auth.type, but It is observed in the JDBC Interpreter that:

• Setting zeppelin.jdbc.auth.type to KERBEROS didn't work
• Setting default.zeppelin.jdbc.auth.type to KERBEROS works

In protected boolean isKerboseEnabled(), we use getProperty("zeppelin.jdbc.auth.type"), but in public Connection getConnection(String dbPrefix, InterpreterContext context), jdbcUserConfigurations.getPropertyMap(dbPrefix).getProperty("zeppelin.jdbc.auth.type", "SIMPLE") was used.

See also: https://github.com/apache/zeppelin/pull/4029