Write clear text data into ZK znodes

Writing in clear text format into ZK znodes helps with
debugging when cross checking ZK data with Gerrit logs
is required.

Change-Id: Id97e3ebd5cebb56d95a031b10218a3582be1bc24
diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/dfsrefdb/zookeeper/ZkSharedRefDatabase.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/dfsrefdb/zookeeper/ZkSharedRefDatabase.java
index b02db38..97f6be5 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/dfsrefdb/zookeeper/ZkSharedRefDatabase.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/validation/dfsrefdb/zookeeper/ZkSharedRefDatabase.java
@@ -18,9 +18,8 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.inject.Inject;
 import com.googlesource.gerrit.plugins.multisite.validation.dfsrefdb.SharedRefDatabase;
-import java.io.ByteArrayOutputStream;
-import java.io.DataOutputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import javax.inject.Named;
 import org.apache.curator.RetryPolicy;
 import org.apache.curator.framework.CuratorFramework;
@@ -32,10 +31,6 @@
 public class ZkSharedRefDatabase implements SharedRefDatabase {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
-  private static final byte[] ZEROS_OBJECT_ID = {
-    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-  };
-
   private final CuratorFramework client;
   private final RetryPolicy retryPolicy;
 
@@ -97,17 +92,10 @@
   }
 
   static ObjectId readObjectId(byte[] value) {
-    return ObjectId.fromRaw(value);
+    return ObjectId.fromString(value, 0);
   }
 
-  static byte[] writeObjectId(ObjectId value) throws IOException {
-    if (value == null) {
-      return ZEROS_OBJECT_ID;
-    }
-
-    final ByteArrayOutputStream out = new ByteArrayOutputStream();
-    final DataOutputStream stream = new DataOutputStream(out);
-    value.copyRawTo(stream);
-    return out.toByteArray();
+  static byte[] writeObjectId(ObjectId value) {
+    return ObjectId.toString(value).getBytes(StandardCharsets.US_ASCII);
   }
 }