ONOS-5905 transient field 'driver' shouldn't be serialized

Change-Id: I2a54a6515fa98c11b1579c2fed95e8ffaf6d9a85
diff --git a/core/api/src/main/java/org/onosproject/net/AbstractProjectableModel.java b/core/api/src/main/java/org/onosproject/net/AbstractProjectableModel.java
index f155870..48c1711 100644
--- a/core/api/src/main/java/org/onosproject/net/AbstractProjectableModel.java
+++ b/core/api/src/main/java/org/onosproject/net/AbstractProjectableModel.java
@@ -44,7 +44,7 @@
     // Static reference to the driver service; injected via setDriverService
     private static DriverService driverService;
 
-    private Driver driver;
+    private transient Driver driver;
 
     // For serialization
     public AbstractProjectableModel() {