Correct stack identity when delete nested

1. Update an aws asg with invalid 'VPCZoneIdentifier',
the stack update failed.
2. Update again, the stack is always in 'UPDATE_IN_PROGRESS'.

We remove the backup resources first when updating,
but the backup of stack_resource can't be deleted,
due we set an incorrect name of stack_identity before
rpc calling 'delete_stack', due the name is not match the
nested_stack's name.

Change-Id: I89966d0124607c233ac9a82f1ce14f4f2deb3f9b
Closes-Bug: #1478480
(cherry picked from commit ab234eb658)

heat/engine/resources/stack_resource.py

@@ -398,10 +398,15 @@ class StackResource(resource.Resource):
         '''
         Delete the nested stack.
         '''
-        stack_identity = identifier.HeatIdentifier(
-            self.context.tenant_id,
-            self.physical_resource_name(),
-            self.resource_id)
+        try:
+            stack = self.nested()
+        except exception.NotFound:
+            return
+
+        if stack is None:
+            return
+
+        stack_identity = stack.identifier()
 
         try:
             self.rpc_client().delete_stack(self.context, stack_identity)

heat/tests/test_nested_stack.py

@@ -355,11 +355,12 @@ Outputs:
     def test_handle_delete(self):
         self.res.rpc_client = mock.MagicMock()
         self.res.action = self.res.CREATE
+        self.res.nested = mock.MagicMock()
         stack_identity = identifier.HeatIdentifier(
             self.ctx.tenant_id,
             self.res.physical_resource_name(),
             self.res.resource_id)
-
+        self.res.nested().identifier.return_value = stack_identity
         self.res.handle_delete()
         self.res.rpc_client.return_value.delete_stack.assert_called_once_with(
-            self.ctx, stack_identity)
+            self.ctx, self.res.nested().identifier())

heat/tests/test_provider_template.py

@@ -924,9 +924,13 @@ class TemplateResourceCrudTest(common.HeatTestCase):
         self.res.uuid = six.text_type(uuid.uuid4())
         self.res.resource_id = six.text_type(uuid.uuid4())
         self.res.action = self.res.CREATE
+        self.res.nested = mock.MagicMock()
         ident = identifier.HeatIdentifier(self.ctx.tenant_id,
                                           self.res.physical_resource_name(),
                                           self.res.resource_id)
+        self.res.nested().identifier.return_value = ident
         self.res.handle_delete()
         rpcc = self.res.rpc_client.return_value
-        rpcc.delete_stack.assert_called_once_with(self.ctx, ident)
+        rpcc.delete_stack.assert_called_once_with(
+            self.ctx,
+            self.res.nested().identifier())

heat/tests/test_stack_resource.py

@@ -496,14 +496,19 @@ class StackResourceTest(common.HeatTestCase):
                           force_reload=True)
         self.m.VerifyAll()
 
-    def test_delete_nested_not_found_nested_stack(self):
-
+    def test_delete_nested_none_nested_stack(self):
         self.parent_resource._nested = None
+        self.assertIsNone(self.parent_resource.delete_nested())
+
+    def test_delete_nested_not_found_nested_stack(self):
+        self.parent_resource._nested = mock.MagicMock()
         rpcc = mock.Mock()
         self.parent_resource.rpc_client = rpcc
         rpcc.return_value.delete_stack = mock.Mock(
             side_effect=exception.NotFound())
         self.assertIsNone(self.parent_resource.delete_nested())
+        rpcc.return_value.delete_stack.assert_called_once_with(
+            self.parent_resource.context, mock.ANY)
 
     def test_need_update_in_failed_state_for_nested_resource(self):
         """