I think start_response must called inside pseudo-app to keep WSGI

gods happy. Start_response wasn't getting called prior to this fix
if user token was invalid.

Change-Id: I84b0f6790cfd9f2c479f81951974bd5e51ba2fd1
Closes-Bug: #1648274

src/config/api-server/vnc_auth_keystone.py

@@ -263,6 +263,7 @@ def get_auth_headers_from_token(self, request, token):
         conf_info['delay_auth_decision'] = True
 
         def token_to_headers(env, start_response):
+            start_response('200 OK', [('Content-type', 'text/plain')])
             status = env.get('HTTP_X_IDENTITY_STATUS')
             if status and status.lower() == 'invalid':
                 return {}
@@ -273,7 +274,6 @@ def token_to_headers(env, start_response):
                 hdr_val = env.get(hdr_name)
                 if hdr_val:
                     ret_headers_dict[hdr_name] = hdr_val
-            start_response('200 OK', [('Content-type', 'text/plain')])
             return ret_headers_dict
 
         auth_middleware = auth_token.AuthProtocol(token_to_headers, conf_info)