bug fix: Set default flags for virDomain.state() function

Some libvirt versions do not set the default value for flags, so we need to
explicity set it.

libvirt.virDomain.state = state(self, flags) unbound libvirt.virDomain method

Otherwise, the following error will be raised

[06/Mar/2014:23:40:05] HTTP Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/cherrypy/_cprequest.py", line 656, in respond
    response.body = self.handler()
  File "/usr/lib/python2.7/dist-packages/cherrypy/lib/encoding.py", line 188, in __call__
    self.body = self.oldhandler(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/cherrypy/_cpdispatch.py", line 34, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "/home/alinefm/kimchi/src/kimchi/control/base.py", line 71, in wrapper
    ident = fn(*model_args)
  File "/home/alinefm/kimchi/src/kimchi/model/networks.py", line 214, in deactivate
    if self._get_vms_attach_to_a_network(name, "running"):
  File "/home/alinefm/kimchi/src/kimchi/model/networks.py", line 199, in _get_vms_attach_to_a_network
    state == dom.state()[0]):
  File "/home/alinefm/kimchi/src/kimchi/model/libvirtconnection.py", line 62, in wrapper
    ret = f(*args, **kwargs)
TypeError: state() takes exactly 2 arguments (1 given)

Signed-off-by: Aline Manera <alinefm@br.ibm.com>