Remove 'MultiattachSupportNotYetAvailable' exception

With the removal of cinder < v3.44 support and cells v1 support, there
is no longer anything raising the aforementioned exception. Remove
references to it.

Part of blueprint remove-cells-v1

Change-Id: I79bc1cdab28474d8e979ef9b7a07b674013d2ac3
Signed-off-by: Stephen Finucane <[email protected]>

Author: stephenfin

nova/api/openstack/compute/volumes.py

@@ -339,8 +339,7 @@ def create(self, req, server_id, body):
             raise exc.HTTPNotFound(explanation=e.format_message())
         except (exception.InstanceIsLocked,
                 exception.DevicePathInUse,
-                exception.MultiattachNotSupportedByVirtDriver,
-                exception.MultiattachSupportNotYetAvailable) as e:
+                exception.MultiattachNotSupportedByVirtDriver) as e:
             raise exc.HTTPConflict(explanation=e.format_message())
         except exception.InstanceInvalidState as state_error:
             common.raise_http_conflict_for_instance_invalid_state(state_error,

nova/exception.py

@@ -282,14 +282,6 @@ class MultiattachNotSupportedByVirtDriver(NovaException):
     code = 409
 
 
-class MultiattachSupportNotYetAvailable(NovaException):
-    # This exception indicates the deployment is not yet new enough to support
-    # multiattach volumes, so a 409 HTTPConflict response is generally used
-    # for handling this in the API.
-    msg_fmt = _("Multiattach volume support is not yet available.")
-    code = 409
-
-
 class MultiattachNotSupportedOldMicroversion(Invalid):
     msg_fmt = _('Multiattach volumes are only supported starting with '
                 'compute API version 2.60.')

nova/tests/unit/api/openstack/compute/test_volumes.py

@@ -924,21 +924,6 @@ def test_attach_with_multiattach_fails_old_microversion(self):
         self.assertIn('Multiattach volumes are only supported starting with '
                       'compute API version 2.60', six.text_type(ex))
 
-    def test_attach_with_multiattach_fails_not_available(self):
-        """Tests the case that the user tries to attach with a
-        multiattach volume on cells v1 where multiattach volumes are
-        not supported.
-        """
-        with mock.patch.object(
-                self.controller.compute_api, 'attach_volume',
-                side_effect=
-                exception.MultiattachSupportNotYetAvailable) as attach:
-            ex = self.assertRaises(webob.exc.HTTPConflict, self._post_attach)
-        create_kwargs = attach.call_args[1]
-        self.assertTrue(create_kwargs['supports_multiattach'])
-        self.assertIn('Multiattach volume support is not yet available',
-                      six.text_type(ex))
-
     def test_attach_with_multiattach_fails_not_supported_by_driver(self):
         """Tests the case that the user tries to attach with a
         multiattach volume but the compute hosting the instance does