Segment fault with wrong file permissions

[ecomaikgolf]

If a non-privileged user -u executes fiche with the log file -l in /var/log (without writing permissions) the program will crash with "Segment fault (core dumped)"

Tested on Ubuntu 18.04 with lastest version of fiche.

[foursixnine]

#94 adds a fix for this, via systemd unit. But I guess a check for write permissions shouldn't be too much of a problem...