Lock down docker install to 18.09.5

Change-Id: I7bf2801e7b31024d9cdb1b45a95e5ac2fd8248de
Issue-ID: OOM-1598
Signed-off-by: Gary Wu <gary.i.wu@huawei.com>
diff --git a/deployment/heat/onap-rke/parts/onap-oom-1.yaml b/deployment/heat/onap-rke/parts/onap-oom-1.yaml
index b1676b2..4654859 100644
--- a/deployment/heat/onap-rke/parts/onap-oom-1.yaml
+++ b/deployment/heat/onap-rke/parts/onap-oom-1.yaml
@@ -66,7 +66,7 @@
 
   docker_version:
     type: string
-    default: "17.03.2"
+    default: "18.09.5"
 
   rancher_version:
     type: string