stats don't get cleared after shutting down the systemd service about fdns

[startx2017]

Fixed in fdns, need to port it to firetools. There is an up to 10s delay until the monitor detects fdns went down.

[glitsj16]

@startx2017 Thanks for the work on this. The monitor now makes much more sense. But /dev/shm/fdns.stats still stays present after fdns stop (at least on Arch Linux, haven't tested Ubuntu yet). Maybe that's the 'new' intended behaviour? As stated above it can be easily cleaned up in the systemd service via a simple ExecStopPost command. But users that don't use the systemd service will have to take some other action.

[netblue30]

But /dev/shm/fdns.stats still stays present after fdns stop

If the user does a "sudo pkill fdns" we get a chance to remove the file by intercepting the signal before the process gets killed. However if the kernel decides to kill the process (equivelent to kill -9), the process will just be killed without receiving a signal first.

I'll bring in the signal part, but let's put in ExecStopPost also, is like a best effort.

[glitsj16]

... let's put in ExecStopPost also, is like a best effort

Done in bd89850. We can adjust the ExecStopPost command later when the signal part is implemented. Although 'rm -f /dev/shm/fdns-stats' does the job for now, it would be cleaner to have something like '/usr/bin/fdns --clear-stats'. Just a thought...