Fixed the issue ONOS-4949, problem was on Integer.parseInt(id.uri().getSchemeSpecificPart()), the scheme specific part of the device uri was encoded as hexadecimal, and thus for devices with id 0a this method failed

Change-Id: I14efa485d3d23340ef141fa5780b2797e0c39250
diff --git a/providers/null/src/main/java/org/onosproject/provider/nil/CustomTopologySimulator.java b/providers/null/src/main/java/org/onosproject/provider/nil/CustomTopologySimulator.java
index 50647ee..9470a48 100644
--- a/providers/null/src/main/java/org/onosproject/provider/nil/CustomTopologySimulator.java
+++ b/providers/null/src/main/java/org/onosproject/provider/nil/CustomTopologySimulator.java
@@ -78,7 +78,7 @@
      * @param portCount number of device ports
      */
     public void createDevice(DeviceId id, String name, Device.Type type, int portCount) {
-        int chassisId = Integer.parseInt(id.uri().getSchemeSpecificPart());
+        int chassisId = Integer.parseInt(id.uri().getSchemeSpecificPart(), 16);
         createDevice(id, chassisId, type, portCount);
         nameToId.put(name, id);
     }