Undetached JcrItemModel log when opening document revision history

Reproduction path

1. Open a document
2. Open its revision history: make sure there is at least a revision in history.
3. The console produces some warning logs like:

   [INFO] [talledLocalContainer] 28.10.2015 14:09:46 WARN  http-nio-8080-exec-1 [JcrItemModel.writeObject:352] Undetached JcrItemModel /content/documents/myhippoproject/test
   [INFO] [talledLocalContainer] 28.10.2015 14:09:49 WARN  http-nio-8080-exec-2 [JcrItemModel.writeObject:352] Undetached JcrItemModel /content/documents/myhippoproject/test
   [INFO] [talledLocalContainer] 28.10.2015 14:09:52 WARN  http-nio-8080-exec-8 [JcrItemModel.writeObject:352] Undetached JcrItemModel /content/documents/myhippoproject/test
   [INFO] [talledLocalContainer] 28.10.2015 14:09:53 WARN  http-nio-8080-exec-10 [JcrItemModel.writeObject:352] Undetached JcrItemModel /content/documents/myhippoproject/tes