Fix and improve SSL configuration

Previously --insecure argument didn't have any effect
on discover-tempest-config's behavior which lead to to failing
requests due to certificates verify failures. That is fixed now.

Due to the change discover-tempest-config can now automatically
set the following 2 tempest options:
* CONF.identity.disable_ssl_certificate_validation - previously always
  set to True by default.
* CONF.identity.ca_certificates_file - previously not set at all.

Change-Id: Iafcc9720e45190e6bd1046540d7c4a640c043023

config_tempest/main.py

@@ -488,10 +488,15 @@ def get_cloud_creds(args_namespace):
 
     cloud_creds = cloud.config.get_auth_args()
     region_name = cloud.config.config['region_name']
-
     if region_name:
         cloud_creds['region_name'] = region_name
 
+    request_args = cloud.config.get_requests_verify_args()
+    cloud_creds['request_args'] = {
+        'verify': request_args[0],
+        'cert': request_args[1],
+    }
+
     return cloud_creds
 
 
@@ -512,7 +517,9 @@ def config_tempest(**kwargs):
                 accounts_path,
                 kwargs.get('cloud_creds'))
 
-    credentials = Credentials(conf, not kwargs.get('non_admin', False))
+    request_args = kwargs.get('cloud_creds', {}).get('request_args', {})
+    credentials = Credentials(conf, not kwargs.get('non_admin', False),
+                              **request_args)
     clients = ClientManager(conf, credentials)
 
     if kwargs.get('create', False) and kwargs.get('test_accounts') is None: