Change scope to protected

Change-Id: I92b70970b8fa3d89856932ffdff5e9fb744b15d5
diff --git a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/SwitchEvent.java b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/SwitchEvent.java
index 0a25c47..5aa7008 100644
--- a/src/main/java/net/onrc/onos/ofcontroller/networkgraph/SwitchEvent.java
+++ b/src/main/java/net/onrc/onos/ofcontroller/networkgraph/SwitchEvent.java
@@ -1,8 +1,6 @@
 package net.onrc.onos.ofcontroller.networkgraph;
 
 import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.List;
 
 /**
  * Self-contained Switch Object
@@ -11,7 +9,7 @@
  *
  */
 public class SwitchEvent {
-    private final Long dpid;
+    protected final Long dpid;
 
     /**
      * Default constructor.