'Fire up connection. Return non-empty string on success.
Also registers self.disconnected method in the owner\'s dispatcher.
Called internally.'

def plugin(self, owner):

    if (not self._server):
        self._server = (self._owner.Server, 5222)
    if self.use_srv:
        server = self.srv_lookup(self._server)
    else:
        server = self._server
    if (not self.connect(server)):
        return
    self._owner.Connection = self
    self._owner.RegisterDisconnectHandler(self.disconnected)
    return 'ok'
