Add an --undercloud-connection argument

This script isn't only used for local ansible inventories, it is also
called by tripleoclient commands which then pass the generated
inventory into mistral. This means there need to be the option of
making the undercloud connection use ssh, since this is now what
mistral requires.

Change-Id: If4d877dbb144947347afe1de7a06f623d2db3941
Partial-Bug: #1822518
Depends-On: https://review.openstack.org/#/c/648899/

scripts/tripleo-ansible-inventory

@@ -21,15 +21,15 @@
 
 from __future__ import print_function
 
+import json
 import os
 import sys
-import json
 import traceback
 
 from oslo_config import cfg
 from six.moves import configparser
 
-from tripleo_common.inventory import TripleoInventory
+from tripleo_common import inventory as inv
 from tripleo_validations import utils
 
 
@@ -53,7 +53,10 @@ opts = [
                               'as --plan. If both are specified, --stack '
                               'will take precedence.')),
     cfg.StrOpt('ansible_ssh_user', default=os.environ.get('ANSIBLE_SSH_USER',
-        'heat-admin')),
+               'heat-admin')),
+    cfg.StrOpt('undercloud-connection', default=inv.UNDERCLOUD_CONNECTION_SSH,
+               help=('Ansible connection to the undercloud, either "local" '
+                     'or "ssh". Defaults to "local".')),
     cfg.StrOpt('ansible_python_interpreter', default=None),
     cfg.BoolOpt('debug', help='Print tracebacks for exceptions')
 ]
@@ -108,7 +111,7 @@ def write_static_inventory(inventory_file_path, inventory):
                 vars_section_name = "%s:%s" % (section_name, 'vars')
                 config.add_section(vars_section_name)
                 for var, value in section['vars'].items():
-                    if value != None:
+                    if value is not None:
                         config.set(vars_section_name, var, value)
         config.write(inventory_file)
 
@@ -125,7 +128,7 @@ def main():
         'timeout': 30
     }
 
-    inventory = TripleoInventory(
+    inventory = inv.TripleoInventory(
         session=utils.get_auth_session(auth_variables),
         hclient=utils.get_heat_client(auth_variables),
         auth_url=configs.auth_url,