Bug 1570116

Description of problem:
I wannted to cancel transaction and this was shown. That's ugly and should be handled better.

[root@localhost NetworkManager-ci]# dnf downgrade https://kojipkgs.fedoraproject.org//packages/ipsec-tools/0.8.2/9.fc28/x86_64/ipsec-tools-0.8.2-9.fc28.x86_64.rpm
Failed to set locale, defaulting to C
Last metadata expiration check: 4:11:10 ago on Fri Apr 20 14:07:28 2018.
^CTraceback (most recent call last):                                                  ???% [===                                                                                  ] ---  B/s |   0  B     --:-- ETA
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 416, in _progress_cb
    def _progress_cb(self, cbdata, total, done):
KeyboardInterrupt

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/dnf/util.py", line 220, in new_func
    log_call('Call: %s: %s, %s', name, args[1:], kwargs)
  File "/usr/lib64/python3.6/logging/__init__.py", line 1366, in log
    if not isinstance(level, int):
SystemError: <built-in function isinstance> returned a result with an error set

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/bin/dnf", line 58, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 179, in user_main
    errcode = main(args)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 99, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 115, in cli_run
    cli.run()
  File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 1016, in run
    return self.command.run()
  File "/usr/lib/python3.6/site-packages/dnf/cli/commands/downgrade.py", line 55, in run
    file_pkgs=self.base.add_remote_rpms(self.opts.filenames, strict=False),
  File "/usr/lib/python3.6/site-packages/dnf/base.py", line 1274, in add_remote_rpms
    path = dnf.util._urlopen_progress(path, self.conf)
  File "/usr/lib/python3.6/site-packages/dnf/util.py", line 74, in _urlopen_progress
    librepo.download_packages(targets, failfast=True)
  File "/usr/lib64/python3.6/site-packages/librepo/__init__.py", line 1616, in download_packages
    return _librepo.download_packages(list, failfast)
  File "/usr/lib/python3.6/site-packages/dnf/util.py", line 220, in new_func
    log_call('Call: %s: %s, %s', name, args[1:], kwargs)
  File "/usr/lib64/python3.6/logging/__init__.py", line 1366, in log
    if not isinstance(level, int):
SystemError: <built-in function isinstance> returned a result with an error set




Version-Release number of selected component (if applicable):
dnf-2.7.5-12.fc28.noarch


Steps to Reproduce:
1. dnf downgrade https://kojipkgs.fedoraproject.org//packages/ipsec-tools/0.8.2/9.fc28/x86_64/ipsec-tools-0.8.2-9.fc28.x86_64.rpm
2. press ctrl+c

Actual results:
traceback

Expected results:
just ctrl+c message should be shown

Additional info:
I had one more transaction running in other terminal, not sure if that was causing it