Better error message when failing to create the syslog socket

If for some reason keiretsu fails to create the syslog socket, it will
fail with a `bind` error, which will send you on a wild-goose chase with
netstat and lsof. This makes it fail with a better error message.
Merge pull request #9 from bnordbo/master

Better error message when failing to create the syslog socket