Need to check for empty Optional instead of null

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

@@ -984,11 +984,11 @@ public class OFSwitchHandshakeHandler implements IOFConnectionListener {
 			 */
 			if (m.getErrType() == OFErrorType.BAD_REQUEST &&
 					((OFBadRequestErrorMsg) m).getCode() == OFBadRequestCode.BAD_TYPE) {
-				if (((OFBadRequestErrorMsg) m).getData().getParsedMessage() != null &&
+				if (((OFBadRequestErrorMsg) m).getData().getParsedMessage().isPresent() &&
 					((OFBadRequestErrorMsg) m).getData().getParsedMessage().get() instanceof OFBarrierRequest) {
 					log.warn("Switch does not support Barrier Request messages. Could be an HP ProCurve.");
-				} else if (((OFBadRequestErrorMsg) m).getData().getParsedMessage() == null) {
-					log.warn("Switch may not support Barrier Request messages (we can't know for sure if it's a barrier or not). Could be an Brocade...");
+				} else if (!((OFBadRequestErrorMsg) m).getData().getParsedMessage().isPresent()) {
+					log.warn("Switch may not support Barrier Request messages (we can't know for sure if it's a barrier or not). Could be a Brocade...");
 				}
 			} else {
 				logErrorDisconnect(m);