s3: winbindd: Move calling setup_domain_child() into add_trusted_domain().

s3: winbindd: Move calling setup_domain_child() into add_trusted_domain().

Ensure it only gets called when a new domain is allocated
and added to the list.

This should fix problems with the previous logic where
setup_domain_child() was called in places where an existing
domain was returned.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=10358

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Volker Lendecke <vl@samba.org>
Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Wed Jan  8 20:46:55 CET 2014 on sn-devel-104

(cherry picked from commit ca931e460460ffe46735f98b31db47220772d566)

Autobuild-User(v4-0-test): Karolin Seeger <kseeger@samba.org>
Autobuild-Date(v4-0-test): Fri Jan 10 11:45:03 CET 2014 on sn-devel-104