Revert "[-] attempt to fix MLT for ES2"

This reverts commit 138dbc4.

Author: Kenneth Yu

haystack/backends/elasticsearch2_backend.py

@@ -207,7 +207,7 @@ def more_like_this(self, model_instance, additional_query_string=None,
 
         # Deferred models will have a different class ("RealClass_Deferred_fieldname")
         # which won't be in our registry:
-        model_klass = model_instance.model._meta.concrete_model
+        model_klass = model_instance._meta.concrete_model
 
         index = connections[self.connection_alias].get_unified_index().get_index(model_klass)
         field_name = index.get_content_field()
@@ -219,7 +219,7 @@ def more_like_this(self, model_instance, additional_query_string=None,
         if end_offset is not None:
             params['size'] = end_offset - start_offset
 
-        doc_id = get_identifier(model_instance.object)
+        doc_id = get_identifier(model_instance)
 
         try:
             # More like this Query