added system.linux.system.repo.mcp.salt where missing

Change-Id: Iec33efa97a7638437ddfe280ec3f2c69889e791f
diff --git a/classes/cluster/sl-os-ovs/stacklight/server.yml b/classes/cluster/sl-os-ovs/stacklight/server.yml
index 3a19b44..7d72aac 100644
--- a/classes/cluster/sl-os-ovs/stacklight/server.yml
+++ b/classes/cluster/sl-os-ovs/stacklight/server.yml
@@ -4,6 +4,7 @@
 - system.linux.system.repo.elasticsearch
 - system.linux.system.repo.kibana
 - system.linux.system.repo.mcp.openstack
+- system.linux.system.repo.docker
 - system.elasticsearch.server.cluster
 - system.elasticsearch.server.curator
 - system.kibana.server.single