remote: Improve daemon startup error reporting

remote: Improve daemon startup error reporting

If I toggle enable_tcp in libvirtd.conf and add --listen in
/etc/init.d/libvirtd, I get the unhelpful error:

Starting libvirtd daemon: error: Unable to initialize network sockets.

Running without --daemon provides much more useful info:

sudo libvirtd --listen
11:29:26.117: error : remoteCheckCertFile:270 : Cannot access CA certificate '/etc/pki/CA/cacert.pem': No such file or directory

The daemon architecture makes it difficult to report this useful
info if daemonized, so point users to /var/log/messages and
dropping the --daemon flag if they want more info.