Merge pull request #441 from stephenh/lessnoisyakka

Reduce the amount of duplicate logging Akka does to stdout.

core/src/main/scala/spark/util/AkkaUtils.scala

@@ -30,6 +30,7 @@ private[spark] object AkkaUtils {
     val akkaConf = ConfigFactory.parseString("""
       akka.daemonic = on
       akka.event-handlers = ["akka.event.slf4j.Slf4jEventHandler"]
+      akka.stdout-loglevel = "ERROR"
       akka.actor.provider = "akka.remote.RemoteActorRefProvider"
       akka.remote.transport = "akka.remote.netty.NettyRemoteTransport"
       akka.remote.log-remote-lifecycle-events = on