List all the munin plugins

    CLI Example:

    .. code-block:: bash

        salt '*' munin.list_plugins

def list_plugins():
    '''
    List all the munin plugins

    CLI Example:

    .. code-block:: bash

        salt '*' munin.list_plugins
    '''
    pluginlist = os.listdir(PLUGINDIR)
    ret = []
    for plugin in pluginlist:
        # Check if execute bit
        statf = os.path.join(PLUGINDIR, plugin)
        try:
            executebit = stat.S_IXUSR & os.stat(statf)[stat.ST_MODE]
        except OSError:
            pass
        if executebit:
            ret.append(plugin)
    return ret