Moved MastershipBasedTimestamp

- store.common.impl -> store.impl
-- Note: Timestamp interface is located in store package

Change-Id: I97452a41622d3eb97a0c95c4d7ca827863a37e20
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java
index 516915e..062ae03 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/serializers/MastershipBasedTimestampSerializer.java
@@ -1,6 +1,6 @@
 package org.onlab.onos.store.serializers;
 
-import org.onlab.onos.store.common.impl.MastershipBasedTimestamp;
+import org.onlab.onos.store.impl.MastershipBasedTimestamp;
 
 import com.esotericsoftware.kryo.Kryo;
 import com.esotericsoftware.kryo.Serializer;