Tweak how default filter config is handled for batch grid views.

Not sure I fully understand what happened but this seemed to fix it..

tailbone/views/batch.py

@@ -204,13 +204,14 @@ class BatchGrid(BaseGrid):
         classes should *not* override this, but :meth:`filter_config_extras()`
         instead.
         """
+        defaults = self.filter_config_extras()
         config = self.make_filter_config(
             filter_factory_executed=BooleanSearchFilter,
             filter_type_executed='is',
             executed=False,
             include_filter_executed=True)
-        config.update(self.filter_config_extras())
-        return config
+        defaults.update(config)
+        return defaults
 
     def sort_map(self):
         """