Fix BatchMetaDataUpdate to not close passed in object reader

Change-Id: I0c4815be7205d94e07a745a64b3eb222a6e5a5da
diff --git a/java/com/google/gerrit/server/git/meta/VersionedMetaData.java b/java/com/google/gerrit/server/git/meta/VersionedMetaData.java
index 03ae1a1..87a572a 100644
--- a/java/com/google/gerrit/server/git/meta/VersionedMetaData.java
+++ b/java/com/google/gerrit/server/git/meta/VersionedMetaData.java
@@ -430,7 +430,7 @@
           inserter = null;
         }
 
-        if (reader != null) {
+        if (objReader == null && reader != null) {
           reader.close();
           reader = null;
         }