Fix some unchecked conversion warnings

Change-Id: I5cfb0fceb6ab1d200fb1d7e9849ce458a2aa8ac7
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalDeviceEventSerializer.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalDeviceEventSerializer.java
index 5f97afd..c789c96 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalDeviceEventSerializer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/InternalDeviceEventSerializer.java
@@ -35,6 +35,8 @@
                                Class<InternalDeviceEvent> type) {
         ProviderId providerId = (ProviderId) kryo.readClassAndObject(input);
         DeviceId deviceId = (DeviceId) kryo.readClassAndObject(input);
+
+        @SuppressWarnings("unchecked")
         Timestamped<DeviceDescription> deviceDescription
             = (Timestamped<DeviceDescription>) kryo.readClassAndObject(input);