Correctly detect unconfigured SBD when SBD_DEVICE="" (bnc#865260)

Signed-off-by: Tim Serong <tserong@suse.com>
Set corosync logging to_logfile: no

Signed-off-by: Tim Serong <tserong@suse.com>
Don't add service section to corosync.conf (bnc#865041)

Signed-off-by: Tim Serong <tserong@suse.com>