ViewFilter: Fix reference comparison of Revision

Change-Id: I4bc72df1e8effa394617ef9b3ed6e03718b2a76f
diff --git a/java/com/google/gitiles/ViewFilter.java b/java/com/google/gitiles/ViewFilter.java
index 2e517a1..25d6d7e 100644
--- a/java/com/google/gitiles/ViewFilter.java
+++ b/java/com/google/gitiles/ViewFilter.java
@@ -124,7 +124,7 @@
     }
     Revision r = view.getRevision();
     Revision nr = Revision.normalizeParentExpressions(r);
-    if (r != nr) {
+    if (!r.equals(nr)) {
       res.sendRedirect(view.setRevision(nr).toUrl());
       return true;
     }