Description of problem:
I ran `# dnf migrate groups` and it failed with a backtrace.

Version-Release number of selected component:
python-dnf-1.0.0-1.fc22

Additional info:
reporter:       libreport-2.5.1
cmdline:        /usr/bin/python -OO /bin/dnf-2 migrate
executable:     /bin/dnf-2
kernel:         4.0.0-1.fc22.x86_64
runlevel:       N 5
type:           Python
uid:            0

Truncated backtrace:
subprocess.py:573:check_output:CalledProcessError: Command '[u'/usr/bin/yum-deprecated', u'group', u'list', u'installed']' returned non-zero exit status 1

Traceback (most recent call last):
  File "/bin/dnf-2", line 36, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 185, in user_main
    errcode = main(args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 84, in main
    return _main(base, args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 134, in _main
    cli.run()
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1077, in run
    return self.command.run(self.base.extcmds)
  File "/usr/lib/python2.7/site-packages/dnf-plugins/migrate.py", line 126, in run
    self.migrate_groups()
  File "/usr/lib/python2.7/site-packages/dnf-plugins/migrate.py", line 244, in migrate_groups
    installed = self.get_yum_installed_groups(yum_exec)
  File "/usr/lib/python2.7/site-packages/dnf-plugins/migrate.py", line 252, in get_yum_installed_groups
    "installed"]))
  File "/usr/lib64/python2.7/subprocess.py", line 573, in check_output
    raise CalledProcessError(retcode, cmd, output=output)
CalledProcessError: Command '[u'/usr/bin/yum-deprecated', u'group', u'list', u'installed']' returned non-zero exit status 1

Local variables in innermost frame:
retcode: 1
process: <subprocess.Popen object at 0x7f35bc624e50>
cmd: [u'/usr/bin/yum-deprecated', u'group', u'list', u'installed']
unused_err: None
kwargs: {}
output: ''
popenargs: ([u'/usr/bin/yum-deprecated', u'group', u'list', u'installed'],)