RATIS-1501. Exclude log4j JMSSink, JDBCAppender, and Chainsaw from the generated jar.

[szetszwo]

See https://issues.apache.org/jira/browse/RATIS-1501

[szetszwo]

The following classes are excluded after this change:

$diff a.txt ../apache-ratis-2.3.0-SNAPSHOT-orig/a.txt 
945a946,966
> org/apache/log4j/chainsaw/
> org/apache/log4j/chainsaw/ControlPanel$1.class
> org/apache/log4j/chainsaw/ControlPanel$2.class
> org/apache/log4j/chainsaw/ControlPanel$3.class
> org/apache/log4j/chainsaw/ControlPanel$4.class
> org/apache/log4j/chainsaw/ControlPanel$5.class
> org/apache/log4j/chainsaw/ControlPanel$6.class
> org/apache/log4j/chainsaw/ControlPanel$7.class
> org/apache/log4j/chainsaw/ControlPanel.class
> org/apache/log4j/chainsaw/DetailPanel.class
> org/apache/log4j/chainsaw/EventDetails.class
> org/apache/log4j/chainsaw/ExitAction.class
> org/apache/log4j/chainsaw/LoadXMLAction.class
> org/apache/log4j/chainsaw/LoggingReceiver$Slurper.class
> org/apache/log4j/chainsaw/LoggingReceiver.class
> org/apache/log4j/chainsaw/Main$1.class
> org/apache/log4j/chainsaw/Main.class
> org/apache/log4j/chainsaw/MyTableModel$1.class
> org/apache/log4j/chainsaw/MyTableModel$Processor.class
> org/apache/log4j/chainsaw/MyTableModel.class
> org/apache/log4j/chainsaw/XMLFileHandler.class
985a1007,1008
> org/apache/log4j/jdbc/
> org/apache/log4j/jdbc/JDBCAppender.class
1100a1124
> org/apache/log4j/net/JMSSink.class

[adoroszlai]

Thanks @szetszwo for the patch.