Merge "Ensure that RevWalk in SubmoduleOp is released"

gerrit-server/src/main/java/com/google/gerrit/server/git/SubmoduleOp.java

@@ -365,7 +365,7 @@ public class SubmoduleOp {
   private static DirCache readTree(final Repository pdb, final Ref branch)
       throws MissingObjectException, IncorrectObjectTypeException, IOException {
     final RevWalk rw = new RevWalk(pdb);
-
+    try {
       final DirCache dc = DirCache.newInCore();
       final DirCacheBuilder b = dc.builder();
       b.addTree(new byte[0], // no prefix path
@@ -373,6 +373,9 @@ public class SubmoduleOp {
           pdb.newObjectReader(), rw.parseTree(branch.getObjectId()));
       b.finish();
       return dc;
+    } finally {
+      rw.release();
+    }
   }
 
   private static void logAndThrowSubmoduleException(final String errorMsg,