Update stats views.

def update_views(self):
        """Update stats views."""
        # Call the father's method
        super(Plugin, self).update_views()

        # Add specifics informations
        # Alert only
        for key in ['cpu', 'mem', 'swap']:
            if key in self.stats:
                self.views[key]['decoration'] = self.get_alert(self.stats[key], header=key)