implemented GossipDeviceStore with multi-provider, annotation support

Change-Id: I1953bdc37b28af79703ebcfc9201a71a2af49ab2
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java b/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
index 2005582..3039f32 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
@@ -84,4 +84,11 @@
     public int sequenceNumber() {
         return sequenceNumber;
     }
+
+    // Default constructor for serialization
+    @Deprecated
+    protected OnosTimestamp() {
+        this.termNumber = -1;
+        this.sequenceNumber = -1;
+    }
 }