nsswitch: Don't enumerate all domains with wbinfo -u|-g.

nsswitch: Don't enumerate all domains with wbinfo -u|-g.

By default wbinfo -u|-g should only enumerate the domain winbindd is
joined to. The command can be harmfull if you have e.g. 30 domains and
700k users. Then the parent will collect all information and the
oom-killer will kill winbind. As we still want to support it, you can
enable it the old behaviour with wbinfo --domain='*' -u. This is
a measure that sysadmins don't shoot themself.

https://bugzilla.samba.org/show_bug.cgi?id=10034

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Reviewed-by: Günther Deschner <gd@samba.org>
Autobuild-User(master): Andreas Schneider <asn@cryptomilk.org>
Autobuild-Date(master): Thu Jul 18 11:54:58 CEST 2013 on sn-devel-104