do not hardcode syslog devices

in my specific use case (Debian Jessie), multiple of the candidates exist, which makes the whole thing crash because there are more than one candidates.

regardless, we shouldn't have to guess where syslog can be: it's the stdlib's job to do the right thing and find the right device here.

otherwise this is configurable through the -l switch, so I really don't see the need for this. this commits revert part of the previous commits and restores sanity.