Fix heat plugin support

During the configuration of the heat plugin:
- the 'auth_version' attribute was not set correctly,
- the 'demo_tempestconf' user was not assigned the 'member' role,
- a network within the demo project with a subnet was not
  created.

This was causing the heat plugin to fail.

The 'auth_version' is now set correctly, and the 'demo_tempestconf'
user is assigned the 'member' role when configuring the heat
plugin. Also, a network within the demo project with a subnet
is created.

Story: 2007464
Task: 39151

Change-Id: I6d6f2247ecb13317767ebbf93a413bcaff386141

config_tempest/main.py

@@ -207,7 +207,6 @@ def set_options(conf, deployer_input, non_admin, image_path, overrides=[],
 
     uri = conf.get("identity", "uri")
     if "v3" in uri:
-        conf.set("identity", "auth_version", "v3")
         conf.set("identity", "uri_v3", uri)
     else:
         # TODO(arxcruz) make a check if v3 is enabled
@@ -521,12 +520,13 @@ def config_tempest(**kwargs):
 
     credentials = Credentials(conf, not kwargs.get('non_admin', False))
     clients = ClientManager(conf, credentials)
-    services = Services(clients, conf, credentials)
 
     if kwargs.get('create', False) and kwargs.get('test_accounts') is None:
         users = Users(clients.projects, clients.roles, clients.users, conf)
         users.create_tempest_users()
 
+    services = Services(clients, conf, credentials)
+
     if services.is_service(**{"type": "compute"}):
         flavors = Flavors(clients.flavors, kwargs.get('create', False), conf,
                           kwargs.get('flavor_min_mem', C.DEFAULT_FLAVOR_RAM),