Update ganeti-luxid synopsis

The options --syslog, --no-user-checks, --no-voting,
and --yes-do-it 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-luxid.rst

@@ -9,7 +9,8 @@ ganeti-luxid - Ganeti query daemon
 Synopsis
 --------
 
-**ganeti-luxid** [-f] [-d]
+**ganeti-luxid** [-f] [-d] [--syslog] [--no-user-checks]
+[--no-voting --yes-do-it]
 
 DESCRIPTION
 -----------