[server][dvc] Fix to RocksDB atomic flush usage (#676)

Even though we use the DB Options to enable atomic flush, we were
not passing the list of column family handles into the flush call,
and since our WAL is disabled we did not implicitly get the atomic
flush behavior either.

This commit fixes the usage to ensure atomic flushing of the data
and RMD column families.

More details: https://github.com/facebook/rocksdb/wiki/Atomic-flush

clients/da-vinci-client/src/main/java/com/linkedin/davinci/store/rocksdb/RocksDBStoragePartition.java

@@ -750,7 +750,7 @@ public synchronized Map<String, String> sync() {
           // Since Venice RocksDB database disables WAL, flush will be triggered for every 'sync' to avoid data loss
           // during
           // crash recovery
-          rocksDB.flush(WAIT_FOR_FLUSH_OPTIONS);
+          rocksDB.flush(WAIT_FOR_FLUSH_OPTIONS, columnFamilyHandleList);
         } catch (RocksDBException e) {
           checkAndThrowMemoryLimitException(e);
           throw new VeniceException(