aoi: Safer check for master_routingconfig_subdomain

utils/src/ooinstall/openshift_ansible.py

@@ -114,7 +114,7 @@ def write_inventory_vars(base_inventory, multiple_masters, proxy):
         base_inventory.write('openshift_master_cluster_method=native\n')
         base_inventory.write("openshift_master_cluster_hostname={}\n".format(proxy.hostname))
         base_inventory.write("openshift_master_cluster_public_hostname={}\n".format(proxy.public_hostname))
-    if CFG.settings['master_routingconfig_subdomain']:
+    if CFG.settings.get('master_routingconfig_subdomain', False):
         base_inventory.write("osm_default_subdomain={}\n".format(CFG.settings['master_routingconfig_subdomain']))