ldbedit: Prevent the use of the reveal internals control

ldbedit: Prevent the use of the reveal internals control

This is almost certainly not what you want to do. Providing the output of reveal as the input of modify
will necessarily revivify all dead linked attributes (regardless of --extended-dn or not).

This is extremely unexpected behaviour, so we prevent this from happening.

Signed-off-by: Garming Sam <garming@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12596

Autobuild-User(master): Garming Sam <garming@samba.org>
Autobuild-Date(master): Wed Feb 22 04:23:05 CET 2017 on sn-devel-144