Bug 1183392

Only the `yum-plugin-changelog` package is using python-dateutil. I have pyton-dateutil 2.2 installed, and passing valid strings still works, but passing semi-invalid strings ie "yum changelog 2012-junk tmux" dumps the following instead of the exception message:

```
$ yum changelog 2012-junk tmux
Loaded plugins: changelog, fastestmirror, langpacks
Traceback (most recent call last):
  File "/bin/yum", line 29, in <module>
    yummain.user_main(sys.argv[1:], exit_code=True)
  File "/usr/share/yum-cli/yummain.py", line 371, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/yummain.py", line 174, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/cli.py", line 584, in doCommands
    return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)
  File "/usr/lib/yum-plugins/changelog.py", line 204, in doCommand
    self._since_dto = dateutil_parser.parse(since, fuzzy=True)
  File "/usr/lib/python2.7/site-packages/dateutil/parser.py", line 748, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "/usr/lib/python2.7/site-packages/dateutil/parser.py", line 310, in parse
    res, skipped_tokens = self._parse(timestr, **kwargs)
TypeError: 'NoneType' object is not iterable
```

Also note that there is no such thing as python3-dateutil-1.5 :)

This fixed upstream. ValueError is raised properly. 

>>> from dateutil import parser
>>> parser.parse('2012-junk', fuzzy=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "dateutil/parser.py", line 743, in parse
    return DEFAULTPARSER.parse(timestr, **kwargs)
  File "dateutil/parser.py", line 303, in parse
    raise ValueError("unknown string format")
ValueError: unknown string format
>>> dateutil.__version__
'2.4.0'

OK, since we'll going straight to dateutils 2.4, everything should work.