Removed ClockService<K, V> and replaced its usage with a BiFunction<K, V, Timestamp>

Change-Id: Ide8d979f9361f1aff6727a83733747f4512ef8ff
diff --git a/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java b/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
index b6c3b98..3261f33 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/app/GossipApplicationStore.java
@@ -133,13 +133,13 @@
         apps = storageService.<ApplicationId, Application>eventuallyConsistentMapBuilder()
                 .withName("apps")
                 .withSerializer(serializer)
-                .withClockService((k, v) -> clockService.getTimestamp())
+                .withTimestampProvider((k, v) -> clockService.getTimestamp())
                 .build();
 
         states = storageService.<Application, InternalState>eventuallyConsistentMapBuilder()
                 .withName("app-states")
                 .withSerializer(serializer)
-                .withClockService((k, v) -> clockService.getTimestamp())
+                .withTimestampProvider((k, v) -> clockService.getTimestamp())
                 .build();
 
         states.addListener(new InternalAppStatesListener());
@@ -147,7 +147,7 @@
         permissions = storageService.<Application, Set<Permission>>eventuallyConsistentMapBuilder()
                 .withName("app-permissions")
                 .withSerializer(serializer)
-                .withClockService((k, v) -> clockService.getTimestamp())
+                .withTimestampProvider((k, v) -> clockService.getTimestamp())
                 .build();
 
         log.info("Started");