Update ganeti-confd synopsis

The options -p, -b, --syslog, and --no-user-check were already described
in the description; add them to the synopsis as well.
Signed-off-by: Klaus Aehlig <aehlig@google.com>
Reviewed-by: Petr Pudlak <pudlak@google.com>

man/ganeti-confd.rst

@@ -9,7 +9,8 @@ ganeti-confd - Ganeti conf daemon
 Synopsis
 --------
 
-**ganeti-confd** [-f] [-d]
+**ganeti-confd** [-f] [-d]  [--syslog] [-p *PORT*] [-b *ADDRESS*]
+[--no-user-checks]
 
 DESCRIPTION
 -----------