Split movement group shall...split.

Returning true allows to add movements to existing one, and this group shall
always separate them.

product/ERP5/Document/SplitMovementGroup.py

@@ -39,7 +39,7 @@ class SplitMovementGroup(MovementGroup):
     return {}
 
   def test(self, document, property_dict, **kw):
-    return True, property_dict
+    return False, property_dict
 
   def _separate(self, movement_list):
     return [[[movement], {}] for movement in movement_list]