Switch to upstream postgres docker image for OSS tooling

Change-Id: I1d5dfd4d9985c8bc5d5cc51864b57896d95fda49
diff --git a/docker/swarm/stack/postgresql.yml b/docker/swarm/stack/postgresql.yml
index bdad6fb..7ae4052 100644
--- a/docker/swarm/stack/postgresql.yml
+++ b/docker/swarm/stack/postgresql.yml
@@ -1,7 +1,7 @@
 parameters:
   _param:
     docker_postgresql_replicas: 1
-    docker_image_postgresql: docker-sandbox.sandbox.mirantis.net/vstoiko/oss/postgresql:latest
+    docker_image_postgresql: library/postgres:9.6
     postgresql_admin_user: postgres
     postgresql_admin_user_password: postgrespassword
   docker: