Use dynamic hosts for config node

OpenStack compute nodes are not included to /etc/hosts
on config node. Use system.linux.network.dynamic_hosts
to generate the actual /etc/hosts file.

don't use dynamic_hosts for other nodes because there are
additional 'VIP' hostnames may be used (ctl, msg, dbs, mon)

Change-Id: Iecef46a2553ac88fc2efa14d68983728e855b01f
diff --git "a/\173\043 roles \043\175/infra_config" "b/\173\043 roles \043\175/infra_config"
index 0bddd76..49a68ab 100644
--- "a/\173\043 roles \043\175/infra_config"
+++ "b/\173\043 roles \043\175/infra_config"
@@ -7,5 +7,6 @@
           classes:
 #}
           - cluster.${_param:cluster_name}.infra.config
+          - system.linux.network.dynamic_hosts
           - environment.{{ cookiecutter._env_name }}.reclass_datasource_local
           - environment.{{ cookiecutter._env_name }}
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