Reload functionality is broken in Ussuri

[Abhishek Kekane]

Reload config files doesn't work upon sending sighup signal to glance-api service parent process, resulting in terminating the parent and keeping child processes orphan.

[Abhishek Kekane (abhishek-kekane)]

We have removed ssl support [1] this cycle which results in removing some ssl related config options, but we didn't removed all of its usage and two config options 'key_file' and 'cert_file' are still used in reload functionality [2] which is causing error when SIGHUP is sent to parent process and results in termination due to error and childs remaining stale.

If I comment/remove those two options from [2] then SIGHUP works just fine.

[1] https://review.opendev.org/#/c/697969/5/glance/common/wsgi.py
[2] https://github.com/openstack/glance/blob/master/glance/common/utils.py (L560, L561, L562)

I have verified the same by adding new store to enabled_backends config option and it is crating the new store (file) as well as adding image to this newly created store.