Merge "Fix kolla_docker_namespace comment"

Author: Zuul

etc/kayobe/kolla.yml

@@ -86,7 +86,7 @@
 # case Quay.io will be used.
 #kolla_docker_registry:
 
-# Docker namespace to use for Kolla images. Default is 'kolla'.
+# Docker namespace to use for Kolla images. Default is 'openstack.kolla'.
 #kolla_docker_namespace:
 
 # Username to use to access a docker registry. Default is not set, in which