[arch-mirrors] mirror.f4st.host out of sync

Hello, Unfortunately, the mirror.f4st.host (mirror.fs.cx) was out of sync since 28 December 2015. The issue was a lock file which was not removed automatically. It is now fixed and the mirror is now synced again. In addition, I have added a monitoring script which alerts me if the mirror is out of sync for more than 12h. Best regards, Florian