Publish cluster changes to event bus, see #2202

* ClusterEventBus
* Removed register listener and related
* Removed Gossip.meta because it doesn't handle version conflicts

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

@@ -11,6 +11,8 @@ import akka.testkit._
 import scala.concurrent.util.duration._
 import scala.collection.immutable.SortedSet
 import java.util.concurrent.atomic.AtomicReference
+import akka.actor.Props
+import akka.actor.Actor
 
 object NodeUpMultiJvmSpec extends MultiNodeConfig {
   val first = role("first")
@@ -27,6 +29,7 @@ abstract class NodeUpSpec
   with MultiNodeClusterSpec {
 
   import NodeUpMultiJvmSpec._
+  import ClusterEvent._
 
   "A cluster node that is joining another cluster" must {
     "be moved to UP by the leader after a convergence" taggedAs LongRunningTest in {
@@ -39,12 +42,13 @@ abstract class NodeUpSpec
     "be unaffected when joining again" taggedAs LongRunningTest in {
 
       val unexpected = new AtomicReference[SortedSet[Member]](SortedSet.empty)
-      cluster.registerListener(new MembershipChangeListener {
-        def notify(members: SortedSet[Member]) {
-          if (members.size != 2 || members.exists(_.status != MemberStatus.Up))
-            unexpected.set(members)
+      cluster.subscribe(system.actorOf(Props(new Actor {
+        def receive = {
+          case MembersChanged(members) ⇒
+            if (members.size != 2 || members.exists(_.status != MemberStatus.Up))
+              unexpected.set(members)
         }
-      })
+      })), classOf[MembersChanged])
       enterBarrier("listener-registered")
 
       runOn(second) {