[ci][nova] Server {uuid} failed to delete

Hi, The gate is in a bad shape due to frequent failure of server delete tests due to placement conflicts. The bug that is tracked in [1] became more frequent after a recent placement feature (consumer_types) got landed. The nova team is aware of the situation and possible fixes are being discussed [2]. Cheers, gibi [1] http://status.openstack.org/elastic-recheck/#1836754 [2] https://review.opendev.org/q/topic:bug/1836754