What were you trying to do that didn't work?

I was trying to generate a custom SELinux policy for an application.

What is the impact of this issue to you?

I cannot create the custom policy.

Please provide the package NVR for which the bug is seen:

policycoreutils-devel-3.7-1.el10.x86_64

How reproducible is this bug?:

Easy

Steps to reproduce

1. Run `sepolicy generate --init /usr/bin/true`

Expected results

Policy is created.

Actual results

Displays this error message:

```

Errors during downloading metadata for repository 'baseos':
  - Status code: 404 for https://mirrors.centos.org/metalink?repo=centos-baseos-$stream&arch=x86_64&protocol=https,http (IP: 152.19.134.142)
  - Status code: 404 for https://mirrors.centos.org/metalink?repo=centos-baseos-$stream&arch=x86_64&protocol=https,http (IP: 67.219.144.68)
  - Status code: 404 for https://mirrors.centos.org/metalink?repo=centos-baseos-$stream&arch=x86_64&protocol=https,http (IP: 140.211.169.196)
Traceback (most recent call last):
  File "/usr/lib/python3.12/site-packages/dnf/repo.py", line 574, in load
    ret = self._repo.load()
          ^^^^^^^^^^^^^^^^^
  File "/usr/lib64/python3.12/site-packages/libdnf/repo.py", line 467, in load
    return _repo.Repo_load(self)
           ^^^^^^^^^^^^^^^^^^^^^
libdnf._error.Error: Failed to download metadata for repo 'baseos': Cannot prepare internal mirrorlist: Status code: 404 for https://mirrors.centos.org/metalink?repo=centos-baseos-$stream&arch=x86_64&protocol=https,http (IP: 67.219.144.68)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/sepolicy", line 702, in <module>
    args.func(args)
  File "/usr/bin/sepolicy", line 569, in generate
    mypolicy.gen_writeable()
  File "/usr/lib/python3.12/site-packages/sepolicy/generate.py", line 1304, in gen_writeable
    self.__extract_rpms()
  File "/usr/lib/python3.12/site-packages/sepolicy/generate.py", line 1271, in __extract_rpms
    base.fill_sack(load_system_repo=True)
  File "/usr/lib/python3.12/site-packages/dnf/base.py", line 413, in fill_sack
    self._add_repo_to_sack(r)
  File "/usr/lib/python3.12/site-packages/dnf/base.py", line 141, in _add_repo_to_sack
    repo.load()
  File "/usr/lib/python3.12/site-packages/dnf/repo.py", line 581, in load
    raise dnf.exceptions.RepoError(str(e))
dnf.exceptions.RepoError: Failed to download metadata for repo 'baseos': Cannot prepare internal mirrorlist: Status code: 404 for https://mirrors.centos.org/metalink?repo=centos-baseos-$stream&arch=x86_64&protocol=https,http (IP: 67.219.144.68)

```

It looks like the $stream variable is not getting substituted in the URL. Replacing it with 10-stream and using wget manually downloads the file.