[PATCH] busybox: fix for syslog service in systemd

[<mingli.yu@windriver.com>]

commit 9943ffeeed5c612d1bc44a12607d553f7704dc7e
Author: Chen Qi <Qi.Chen@windriver.com>
Date:   Thu Sep 11 04:55:35 2014 -0400

    busybox: fix for syslog service in systemd
    
    This patch includes the following changes:
    1. Explicitly set StandardOutput of the log daemon to null.
       This would avoid creating a feedback loop of the syslog service.
       See link below for more information.
       http://www.freedesktop.org/wiki/Software/systemd/syslog/
    
    2. Use ALTERNATIVE machanism to manage the syslog service file.
       This is because that other package may also provide a syslog
       implementation.
    
    3. Make the syslog daemon socket activated only. Otherwise, things
       would crash if we install busybox-syslog and other syslog packages
       together in one image.
    
    Signed-off-by: Chen Qi <Qi.Chen@windriver.com>
    Signed-off-by: Mingli Yu <mingli.yu@windriver.com>

commit 425d7b8605612cdc65daf2c1ef6cf5655ad8f227
Author: Yadi.hu <yadi.hu@windriver.com>
Date:   Wed Jun 1 17:54:17 2016 -0700

    busybox: handle syslog
    
    If CONFIG_KLOGD is not enabled, then the related service file should
    not be installed, The error message is below:
    
        Cannot add dependency job for unit busybox-klogd.service,
        ignoring: Unit busybox-klogd.service failed to load:
        No such file or directory.
    
    So we should first check the configuration before we install these
    service files.
    
    Signed-off-by: Yadi.hu <yadi.hu@windriver.com>
    Signed-off-by: Mingli Yu <mingli.yu@windriver.com>