ModelStorage._clean_defaults must skip related fields

Related fields like '.rec_name' could be set as default value, they are not
defined in _fields and they must be cleaned.

issue5376
review17131002

trytond/model/modelstorage.py

@@ -1137,6 +1137,8 @@ class ModelStorage(Model):
         pool = Pool()
         vals = {}
         for field in defaults.keys():
+            if '.' in field:  # skip all related fields
+                continue
             fld_def = cls._fields[field]
             if fld_def._type in ('many2one', 'one2one'):
                 if isinstance(defaults[field], (list, tuple)):