Description of problem:
dnf history undo 27

Version-Release number of selected component:
dnf-0.2.17-1.git6a055e6.fc18

Additional info:
cmdline:        /usr/bin/python /bin/dnf history undo 27
executable:     /bin/dnf
kernel:         3.7.2-204.fc18.x86_64
uid:            0

Truncated backtrace:
__init__.py:2781:remove:KeyError: 'pattern'

Traceback (most recent call last):
  File "/bin/dnf", line 35, in <module>
    main.user_main(sys.argv[1:], exit_code=True)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 314, in user_main
    errcode = main(args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 141, in main
    result, resultmsgs = cli.do_commands()
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1457, in do_commands
    return command.doCommand(self.base.basecmd, self.base.extcmds)
  File "/usr/lib/python2.7/site-packages/dnf/cli/commands.py", line 2262, in doCommand
    ret = self._hcmd_undo(extcmds)
  File "/usr/lib/python2.7/site-packages/dnf/cli/commands.py", line 2128, in _hcmd_undo
    if self.base.history_undo(old):
  File "/usr/lib/python2.7/site-packages/dnf/yum/__init__.py", line 3071, in history_undo
    if self.remove(pkgtup=pkg.pkgtup):
  File "/usr/lib/python2.7/site-packages/dnf/yum/__init__.py", line 2781, in remove
    pattern = kwargs['pattern']
KeyError: 'pattern'

Local variables in innermost frame:
tx_return: []
po: None
self: <dnf.cli.cli.YumBaseCli object at 0x2ca1790>
pkgs: []
kwargs: {'pkgtup': (u'python-dmidecode', u'x86_64', u'0', u'3.10.13', u'6.fc18')}