Updating tower topology for the tutorial.

Change-Id: I860580a1128f34cef8151714893d25b707221730
diff --git a/tools/test/topos/tower.json b/tools/test/topos/tower.json
index 7f7d426..358daf3 100644
--- a/tools/test/topos/tower.json
+++ b/tools/test/topos/tower.json
@@ -2,10 +2,10 @@
   "devices": {
     "of:0000000000000001": { "basic": { "name": "Spine-1" }},
     "of:0000000000000002": { "basic": { "name": "Spine-2" }},
-    "of:0000000000000003": { "basic": { "name": "Leaf-1" }},
-    "of:0000000000000004": { "basic": { "name": "Leaf-2" }},
-    "of:0000000000000005": { "basic": { "name": "Leaf-3" }},
-    "of:0000000000000006": { "basic": { "name": "Leaf-4" }}
+    "of:000000000000000b": { "basic": { "name": "Leaf-1" }},
+    "of:000000000000000c": { "basic": { "name": "Leaf-2" }},
+    "of:000000000000000d": { "basic": { "name": "Leaf-3" }},
+    "of:000000000000000e": { "basic": { "name": "Leaf-4" }}
   },
 
   "hosts": {