I believe changes of Database.java is unnecessary. I reverted it.

Author: hideki

src/main/java/com/couchbase/lite/Database.java

@@ -904,8 +904,10 @@ public Map<String, Object> invoke(Map<String, Object> attachment) {
 
                 int revPos = (Integer) attachment.get("revpos");
                 if (revPos < minRevPos && revPos != 0) {
-                    //nothing changed
-                    return attachment;
+                    Map<String, Object> map = new HashMap<String, Object>();
+                    map.put("stub", true);
+                    map.put("revpos", revPos);
+                    return map;
                 } else {
                     Map<String, Object> expanded = new HashMap<String, Object>();
                     expanded.putAll(attachment);