IMDb: fix match for \u2013

This fixes the following exception:


````
ERROR 2013-08-14T00:38:49 supybot Uncaught exception in ['imdb'].
Traceback (most recent call last):
  File "/home/kytv/test-limnoria/lib/python2.7/site-packages/supybot/callbacks.py", line 1271, in _callCommand
    self.callCommand(command, irc, msg, *args, **kwargs)
  File "/home/kytv/test-limnoria/lib/python2.7/site-packages/supybot/utils/python.py", line 86, in g
    f(self, *args, **kwargs)
  File "/home/kytv/test-limnoria/lib/python2.7/site-packages/supybot/callbacks.py", line 1252, in callCommand
    method(irc, msg, *args, **kwargs)
  File "/home/kytv/test-limnoria/lib/python2.7/site-packages/supybot/commands.py", line 1077, in newf
    f(self, irc, msg, args, *state.args, **state.kwargs)
  File "/home/kytv/test-limnoria/plugins/IMDb/plugin.py", line 144, in imdb
    year = unid(root.xpath('//h1[span/@itemprop="name"]/span[last()]')[0].text.strip().strip(')(').replace(u('\u2013', '-')))
TypeError: u() takes exactly 1 argument (2 given)
ERROR 2013-08-14T00:38:49 supybot Exception id: 0x574fa
````