Suppress custom exceptions thru jmx

startNativeTransport, can send back

org.jboss.netty.channel.ChannelException

which causes jconsole to puke with a bad message such as

Problem invoking startNativeTransport: java.rmi.UnmarshalException: Error unmarshaling return header; nested exception is: java.io.EOFException

convert to RuntimeException so you get something like:

org.jboss.netty.channel.ChannelException: Failed to bind to: localhost/127.0.0.1:9042