Set the plugin list according to the Glances server.

def set_plugins(self, input_plugins):
        """Set the plugin list according to the Glances server."""
        header = "glances_"
        for item in input_plugins:
            # Import the plugin
            try:
                plugin = __import__(header + item)
            except ImportError:
                # Server plugin can not be imported from the client side
                logger.error("Can not import {} plugin. Please upgrade your Glances client/server version.".format(item))
            else:
                # Add the plugin to the dictionary
                # The key is the plugin name
                # for example, the file glances_xxx.py
                # generate self._plugins_list["xxx"] = ...
                logger.debug("Server uses {} plugin".format(item))
                self._plugins[item] = plugin.Plugin(args=self.args)
        # Restoring system path
        sys.path = sys_path