fix q node child type, work with the django-advanced-filters app

Author: tmszi

polymorphic/query_translate.py

@@ -66,7 +66,7 @@ def tree_node_correct_field_specs(my_model, node):
         for i in range(len(node.children)):
             child = node.children[i]
 
-            if type(child) == tuple:
+            if type(child) == tuple or type(child) == list:
                 # this Q object child is a tuple => a kwarg like Q( instance_of=ModelB )
                 key, val = child
                 new_expr = _translate_polymorphic_filter_definition(