Description of problem:

Running dnf swidtags regen fails with traceback.

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

dnf-plugin-swidtags-0.7.2-1.fc31.noarch
python3-libdnf-0.28.0-1.fc31.x86_64

How reproducible:

Deterministic.

Steps to Reproduce:
1. Execute dnf swidtags regen

Actual results:

# dnf swidtags regen
Traceback (most recent call last):
  File "/usr/lib/python3.7/site-packages/dnf/plugin.py", line 104, in _caller
    getattr(plugin, method)()
  File "/usr/lib/python3.7/site-packages/dnf-plugins/swidtags.py", line 136, in config
    self.conf.data[s][o] = DEFAULTS[s][o]
  File "/usr/lib64/python3.7/site-packages/libdnf/conf.py", line 1826, in <lambda>
    __getattr__ = lambda self, name: _swig_getattr(self, ConfigParser, name)
  File "/usr/lib64/python3.7/site-packages/libdnf/conf.py", line 80, in _swig_getattr
    raise AttributeError("'%s' object has no attribute '%s'" % (class_type.__name__, name))
AttributeError: 'ConfigParser' object has no attribute 'data'

Last metadata expiration check: 0:01:55 ago on Fri 15 Mar 2019 10:41:20 AM UTC.
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/python3.7/site-packages/dnf/cli/main.py", line 192, in user_main
    errcode = main(args)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 99, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.7/site-packages/dnf/cli/main.py", line 115, in cli_run
    cli.run()
  File "/usr/lib/python3.7/site-packages/dnf/cli/cli.py", line 1128, in run
    return self.command.run()
  File "/usr/lib/python3.7/site-packages/dnf-plugins/swidtags.py", line 95, in run
    if self.plugin.run_rpm2swidtag_for(p_names) == 0:
  File "/usr/lib/python3.7/site-packages/dnf-plugins/swidtags.py", line 270, in run_rpm2swidtag_for
    rpm2swidtag_command = self.conf.get("main", "rpm2swidtag_command")
  File "/usr/lib64/python3.7/site-packages/libdnf/conf.py", line 1942, in ConfigParser__get
    return self.getSubstitutedValue(section, option)
  File "/usr/lib64/python3.7/site-packages/libdnf/conf.py", line 1870, in getSubstitutedValue
    return _conf.ConfigParser_getSubstitutedValue(self, section, key)
IndexError: OptionReader::getValue(): Missing option rpm2swidtag_command in section main

Expected results:

No error, SWID tags generated.

Additional info: