[CORD-1608]
Fix DNS and ansible timeout issues when building docker images

Change-Id: I549387d458c280ac769e9c3a06a5e035457c0815
diff --git a/scenarios/single/config.yml b/scenarios/single/config.yml
index 4ceb2cb..11ed821 100644
--- a/scenarios/single/config.yml
+++ b/scenarios/single/config.yml
@@ -32,11 +32,15 @@
 prep_headnode_prereqs:
   - prep-buildnode
 
+docker_images_prereqs:
+  - prep-headnode
+
 # single scenario configuration
 frontend_only: False
 use_maas: False
 use_apt_cache: False
 use_openstack: False
+create_configdirs_become: False
 xos_images: []
 
 # whitelist of images for imagebuilder to build/pull (tagged elsewhere)