Reduce size of jenkins logs

Each build is now over 40mb logs.

A lot of DEBUG logging was left on for test failures that have been
fixed. Added an issue # for ones that are still valid or if if it on
as the test verifies debug

akka-cluster/src/multi-jvm/scala/akka/cluster/MultiDcSplitBrainSpec.scala

@@ -23,7 +23,7 @@ object MultiDcSplitBrainMultiJvmSpec extends MultiNodeConfig {
 
   commonConfig(ConfigFactory.parseString(
     """
-      akka.loglevel = DEBUG
+      akka.loglevel = DEBUG # issue #24955
       akka.cluster.debug.verbose-heartbeat-logging = on
       akka.cluster.debug.verbose-gossip-logging = on
       akka.remote.netty.tcp.connection-timeout = 5 s # speedup in case of connection issue