Use the 2.7.3-1 tag for the Rundeck image

Change-Id: I2ee6fc62c961bfd6d211cea39fe7dc17d65d3577
diff --git a/docker/swarm/stack/rundeck.yml b/docker/swarm/stack/rundeck.yml
index f89619a..a4ec24b 100644
--- a/docker/swarm/stack/rundeck.yml
+++ b/docker/swarm/stack/rundeck.yml
@@ -1,7 +1,7 @@
 parameters:
   _param:
     docker_rundeck_replicas: 1
-    docker_image_rundeck: docker-sandbox.sandbox.mirantis.net/ikharin/oss/rundeck:devel
+    docker_image_rundeck: docker-sandbox.sandbox.mirantis.net/ikharin/oss/rundeck:2.7.3-1
   docker:
     client:
       stack: