This patch removes the conditional inclusion of the notification
section of the service configuration. This ensures that oslo.messaging
notifications use the correct transport for deployments that have
separate rpc and notify messaging backends. For example, if the
transport_url isnot provided in the notification section of the
service configuration, the transport_url specified in the default
section will be used instead.
Change-Id: I35f13c4cb14e51e5e164db12011d9c053f1260eb