Fixing tree topology simulator to chose proper edge-ports for host attachment.

Change-Id: I9ab9a26dbe1491068e61df611edb6e41302afa5b

@@ -387,7 +387,7 @@ public abstract class TopologySimulator {
      */
     protected List<PortDescription> buildPorts(int portCount) {
         List<PortDescription> ports = Lists.newArrayList();
-        for (int i = 0; i < portCount; i++) {
+        for (int i = 1; i <= portCount; i++) {
             ports.add(new DefaultPortDescription(PortNumber.portNumber(i), true,
                                                  Port.Type.COPPER, 0));
         }

@@ -55,7 +55,6 @@ public class TreeTopologySimulator extends TopologySimulator {
 
     @Override
     protected void createLinks() {
-
         int portOffset = 1;
         for (int t = 1; t < tierOffset.length; t++) {
             int child = tierOffset[t];
@@ -72,7 +71,7 @@ public class TreeTopologySimulator extends TopologySimulator {
     @Override
     protected void createHosts() {
         for (int i = tierOffset[tierOffset.length - 1]; i < deviceCount; i++) {
-            createHosts(deviceIds.get(i), hostCount);
+            createHosts(deviceIds.get(i), 2);
         }
     }
 }