Do not restore values for created records when exception is raised when saving

Once a record has been created, the id is modified which change its hash value
such that it can not be found anymore.
But as the creation succeeded (and only the write part has failed) we can just
restore the values to None.

Closes #14093
(grafted from a56b25f536568b808bc4c57b6cee03408eaf06f2)

--HG--
branch : 7.0

trytond/trytond/model/modelstorage.py

@@ -1997,8 +1997,8 @@ class ModelStorage(Model):
                         cls.write(*sum(
                                 (([r], save_values[r]) for r in to_write), ()))
             except Exception:
-                for record in to_create + to_write:
-                    record._values = values[record]
+                for record in chain(to_create, to_write):
+                    record._values = values.get(record)
                 raise
             for record in to_create + to_write:
                 record._init_values = None