canlogserver: Fix termination after signal

[yashi]

With f45de1b782c083, we've removed unsafe function exit(3) from the signal handler. But that made canlogserver's accept(3)ing process not exit; It unconditionally keeps running with EINTR.

Check the variable "running" when signaled and exit with an appropriate error code.

[hartkopp]

this commit should be "canlogserver: fix termination after signal"

Because before that there was a proper exit of the application. Also please add a "Fixes:" tag into the commit message.

[yashi]

@hartkopp ping