Do not mount volume to sf-notfier container

As we enabled logging from Docker containers
via journald logging driver

Change-Id: Ibc009596089c47800cd78d0e6bc434f702eb5f96
Related-bug: PROD-27026 (PROD:27026)
diff --git a/docker/swarm/stack/monitoring/sf_notifier.yml b/docker/swarm/stack/monitoring/sf_notifier.yml
index a171ce8..b8b2dd6 100644
--- a/docker/swarm/stack/monitoring/sf_notifier.yml
+++ b/docker/swarm/stack/monitoring/sf_notifier.yml
@@ -29,8 +29,6 @@
               image: ${_param:docker_image_sf_notifier}
               ports:
                 - 15018:5000
-              volumes:
-                - ${prometheus:sf_notifier:dir:logs}:/var/log/sf-notifier
               environment:
                 SF_NOTIFIER_WORKERS: ${_param:sf_notifier_workers}
                 SF_NOTIFIER_BUFFER_SIZE: ${_param:sf_notifier_buffer_size}