Description of problem:
1)install  dnf
2)dnf install  xchat
3)dnf install libvirt
4) dnf history rollback 1
5) dnf history rollback 2

Version-Release number of selected component:
dnf-0.4.9-1.fc20

Additional info:
reporter:       libreport-2.1.9
cmdline:        /usr/bin/python /usr/bin/dnf history rollback 2
executable:     /usr/bin/dnf
kernel:         3.11.9-300.fc20.x86_64
runlevel:       N 5
type:           Python
uid:            0

Truncated backtrace:
base.py:1832:handle_erase:AssertionError

Traceback (most recent call last):
  File "/usr/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 260, in user_main
    errcode = main(args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 63, in main
    return _main(base, args)
  File "/usr/lib/python2.7/site-packages/dnf/cli/main.py", line 122, in _main
    result, resultmsgs = cli.run()
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1471, in run
    return self.command.doCommand(self.base.basecmd, self.base.extcmds)
  File "/usr/lib/python2.7/site-packages/dnf/cli/commands.py", line 2157, in doCommand
    ret = self._hcmd_rollback(extcmds[1:])
  File "/usr/lib/python2.7/site-packages/dnf/cli/commands.py", line 2055, in _hcmd_rollback
    return self.base.history_rollback_transaction(extcmd)
  File "/usr/lib/python2.7/site-packages/dnf/cli/cli.py", line 1067, in history_rollback_transaction
    self.history_undo_operations(operations)
  File "/usr/lib/python2.7/site-packages/dnf/base.py", line 1883, in history_undo_operations
    handle_erase(nevra)
  File "/usr/lib/python2.7/site-packages/dnf/base.py", line 1832, in handle_erase
    assert len(pkgs) == 1
AssertionError

Local variables in innermost frame:
self: <dnf.cli.cli.BaseCli object at 0x13bb750>
old_nevra: u'libvirt-0:1.1.3.1-2.fc20.x86_64'
pkgs: <dnf.query.Query object at 0x14d8780>