Avoid serializing channel to json

src/main/java/net/floodlightcontroller/core/internal/OFSwitchImpl.java

@@ -139,6 +139,7 @@ public class OFSwitchImpl implements IOFSwitch {
         return this.attributes.containsKey(name);
     }
         
+    @JsonIgnore
     public Channel getChannel() {
         return this.channel;
     }
@@ -451,6 +452,7 @@ public class OFSwitchImpl implements IOFSwitch {
      * switch list from being modified out from under the listeners.
      * @return 
      */
+    @JsonIgnore
     public Lock getListenerReadLock() {
         return listenerLock.readLock();
     }
@@ -462,6 +464,7 @@ public class OFSwitchImpl implements IOFSwitch {
      * message from the switch.
      * @return
      */
+    @JsonIgnore
     public Lock getListenerWriteLock() {
         return listenerLock.writeLock();
     }