glance install with `USE_VENV=True` fails

[Cristian Le]

On a fresh Fedora 35 installation `devstack` installation fails with `USE_VENV=True`.
Current blocking bug is with `glance`:
```
cp: cannot stat '/usr/local/etc/glance/rootwrap.*': No such file or directory
```

[Dr. Jens Harbott (j-harbott)]

USE_VENV=True isn't really supported anymore, is there a specific reason you want to use that setup?

[Cristian Le (lecris)]

Why is USE_VENV deprecated? For newcomers, that looks useful for debugging and pinpointing the source of the python library that breaks an installation.

[Dr. Jens Harbott (j-harbott)]

It isn't being tested in the CI, which is why such issues as you are seeing can creep in and stay undetected for a long time. Patches to fix it are of course welcome, but it isn't in the focus of development. One reason for that is that the idea of OpenStack is that all services should be co-installable, which is why we are using a common global requirements definition in order to avoid conflicts.

[Dr. Jens Harbott (j-harbott)]

Not sure why this was reopened.

[Cyril Roelandt (cyril-roelandt)]

Because of this patch https://review.opendev.org/c/openstack/devstack/+/866951 . You mentionned in #3 that "Patches to fix it [were] of course welcome", so I sent one.