Comment 2 for bug 1894966

I can reproduce the problem on the latest master

stack@aio:/opt/stack/nova$ curl -g -i -X POST http://192.168.121.129/compute/v2.1/os-server-groups -H "Accept: application/json" -H "Content-Type: application/json" -H "User-Agent: python-novaclient" -H "X-Auth-Token: $TOKEN" -H "X-OpenStack-Nova-API-Version: 2.1" -d '{"server_group": {"name": "my-grp", "policies": []}}'
HTTP/1.1 500 Internal Server Error
Date: Tue, 15 Sep 2020 10:34:08 GMT
Server: Apache/2.4.29 (Ubuntu)
OpenStack-API-Version: compute 2.1
X-OpenStack-Nova-API-Version: 2.1
Vary: OpenStack-API-Version,X-OpenStack-Nova-API-Version
Content-Type: application/json; charset=UTF-8
Content-Length: 184
x-openstack-request-id: req-6651c4cd-bae4-4011-8975-cb00460d36d3
x-compute-request-id: req-6651c4cd-bae4-4011-8975-cb00460d36d3
Connection: close

{"computeFault": {"code": 500, "message": "Unexpected API Error. Please report this at http://bugs.launchpad.net/nova/ and attach the Nova API log if possible.\n<class 'IndexError'>"}}stack@aio:/opt/stack/nova$