Do not print a message when syslog is not present
Do not print a message when syslog is not present

This is defined as ENOENT when locating the log unix socket.

A missing log socket is often the case in containerized systems like
Docker.  Without this suppression, a lot of log spam results.

RichardKnop/wal-e,wal-e/wal-e,heroku/wal-e,fdr/wal-e,ArtemZ/wal-e,DataDog/wal-e,intoximeters/wal-e,tenstartups/wal-e,nagual13/wal-e,x86Labs/wal-e,equa/wal-e,ajmarks/wal-e