Make heat stack-create work

The stack-create operation fails.  The current implementation of
Heat Ansible role does not implement trusts.  Tell heat it should use
the non-trusts authentication model.

Also add a [keystone_clients] section which is required in newer
versions of heat to properly resolve the keystone v3 API endpoint
required for trust communication.

This fix spawns a Tech-Debt Bug to implement trusts in heat: #1492736

Change-Id: I06dd6436cc34a37b4966fddc888fade982ea51bd
Closes-Bug: #1492648

ansible/roles/heat/templates/heat.conf.j2

@@ -9,6 +9,7 @@ stack_user_domain_name = heat_user_domain
 
 rpc_backend = rabbit
 notification_driver = noop
+deferred_auth_method = password
 
 [oslo_messaging_rabbit]
 rabbit_host = {{ kolla_internal_address }}
@@ -43,3 +44,6 @@ password = {{ heat_keystone_password }}
 
 [ec2authtoken]
 auth_uri = http://{{ kolla_internal_address }}:{{ keystone_public_port }}
+
+[clients_keystone]
+auth_uri = http://{{ kolla_internal_address }}:{{ keystone_public_port }}