Fails to deprovision cluster when swift omits 'content-type'

Description of problem: This is a follow-up to OCPBUGS-2795 and OCPBUGS-2941.

The installer fails to destroy the cluster when the OpenStack object storage omits 'content-type' from responses. This can happen on responses with HTTP status code 204, where a reverse proxy is truncating content-related headers (see this nginX bug report). In such cases, the Installer errors with:

level=error msg=Bulk deleting of container "5ifivltb-ac890-chr5h-image-registry-fnxlmmhiesrfvpuxlxqnkoxdbl" objects failed: Cannot extract names from response with content-type: []

Listing container object suffers from the same issue as listing the containers and this one isn't fixed in latest versions of gophercloud. I've reported https://github.com/gophercloud/gophercloud/issues/2509 and fixing it with https://github.com/gophercloud/gophercloud/issues/2510, however we likely won't be able to backport the bump to gophercloud master back to release-4.8 so we'll have to look for alternatives.

I'm setting the priority to critical as it's causing all our jobs to fail in master.

Version-Release number of selected component (if applicable):

4.8.z

How reproducible:

Likely not happening in customer environments where Swift is exposed directly. We're seeing the issue in our CI where we're using a non-RHOSP managed cloud.

Steps to Reproduce:

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Actual results:

Expected results:

Additional info: