Merge pull request #239 from jboner/wip-1657-support-random-port-√

#1657 - trying to get random port for port 0

akka-remote/src/main/scala/akka/remote/RemoteSettings.scala

@@ -66,7 +66,13 @@ class RemoteSettings(val config: Config, val systemName: String) {
       case ""    ⇒ InetAddress.getLocalHost.getHostAddress
       case value ⇒ value
     }
-    val Port = getInt("akka.remote.server.port")
+    val Port = getInt("akka.remote.server.port") match {
+      case 0 => try {
+        val s = new java.net.ServerSocket(0)
+        try s.getLocalPort finally s.close()
+      } catch { case e => throw new ConfigurationException("Unable to obtain random port", e) }
+      case other => other
+    }
     val ConnectionTimeout = Duration(getMilliseconds("akka.remote.server.connection-timeout"), MILLISECONDS)
 
     val Backlog = getInt("akka.remote.server.backlog")